Fighting has intensified on several fronts in Yemen as the government forces have carried out air attacks on Houthi positions in attempts to retake Mocha, days after the Iran-backed group captured the strategic port city, tightening its grip on the Red Sea – a vital shipping lane.

The Houthis, also known as Ansar Allah (supporters of God), have accused Saudi Arabia of launching more than 100 air attacks on Yemen within the past 48 hours.

Saudi Arabia backs the internationally recognised government, which has described the latest fighting as a “battle for survival”.

The fighting has forced tens of thousands of Yemenis from their homes, including more than 2,000 who headed to Djibouti.

What is the latest situation on the ground? What is the Saudi role in the conflict, and how has Iran responded?

Here’s what we know:

What is the latest situation on the ground?

On Saturday, Yemeni government forces said they had launched air attacks on Houthi fighters along the Red Sea coast after the group seized full control of the strategic shoreline.

Yemen’s government news agency, Saba, reported that “the armed forces destroyed vehicles and weapons and killed members of the Houthi terrorist militia backed by the Iranian regime” near the port city of Mocha.

The spokesperson for the government forces, Majed Abdullah al-Nazili, said they also struck the Houthis’ “vehicles and members” on the Mocha-Dhubab road, 11km (7 miles) from the city, according to Saba.

The government’s attacks came after the Houthis captured Mocha on Thursday and the island of Mayyun (also known as Perim) on Friday, completing their hold on the Bab al-Mandeb strait, a narrow waterway vital to global oil shipping.

On Sunday, Sultan al-Arada, a member of Yemen’s Presidential Leadership Council (PLC) and governor of Marib, said government forces that withdrew from the west coast are currently regrouping in Marib and will return to the battlefield.

In an interview with state-run Saba TV, al-Arada described what happened on the coast as “painful and unfortunate”, but said such setbacks were part of the nature of war.

Al-Arada accused the Houthis of bringing the peace process to a dead end and “forcing the option of war” back on Yemen.

He said government forces were continuing to fight on several fronts and that the ultimate objective in Marib and elsewhere remained “the restoration of the capital, Sanaa”.

“The forces that withdrew are now rearranging themselves, and they will return to the battle again in one form or another,” he said.

The Yemeni military’s reserve Nation Shield Force also claimed on Sunday that the reserve’s 6th Brigade had downed five drones during clashes in the al-Aghbara area, according to a report by Turkish state-run Anadolu news agency.

Separately, the September Net website, which is affiliated with the army of the internationally recognised Yemeni government, reported that air forces conducted a series of air raids against Houthi targets across the country, saying equipment had been destroyed and Houthi fighters killed, but gave no further details on the number of casualties.

Reporting from Sanaa, Yemen, Al Jazeera’s Yousef Mawry said the government forces are trying to recapture territory near the key city of Mocha from the Houthis.

The Al Jazeera correspondent said Saudi Arabia is carrying out air attacks, mainly against Houthi military advances.

“There have been 129 air strikes on the areas that have recently fallen to the Ansar Allah, including areas in the north where the Houthi group is trying to make advances into the city of Marib, a Yemeni government stronghold.”

Mawry said Houthi military buildups in Taiz have also been hit.

He added that there are also reports of clashes on the outskirts of Marib, a government-held city considered to be the economic hub of Yemen. “Whoever controls it, controls Yemen’s revenue stream,” he said.

Mohammed al-Basha, founder and lead analyst of the Basha Report Risk Advisory, told Al Jazeera that political infighting and division within the government forces are stymying the fight against the fast-moving Houthis.

“You’re not going to be able to defeat the Houthis with a split command and control with eight armies sort of competing over influence,” he said.

He blamed infighting among government forces as a reason for the Houthis’ military gains. “They’re finger-pointing and blaming each other,” he added.

Which are the main front lines in Yemen?

The primary active front lines in the latest escalation involve intense fighting between the Iran-backed group and forces aligned with the internationally recognised Yemeni government. These include:

The western coast and Bab al-Mandeb strait: Intense clashes have focused on the coastal areas, including Mocha and Hodeidah, as Houthi forces push towards vital shipping lanes and chokepoints overlooking the Red Sea.

Taiz: Heavy ground battles and counterattacks have taken place in recent days through the mountainous terrain of Taiz province, which acts as a crucial gateway connecting inland areas to the coast.

Marib and al-Jawf: Over the past few weeks, government forces have been battling to defend and expand their control around Marib and the neighbouring northern governorate of al-Jawf bordering Saudi Arabia.

Dhalea: Acting as a vital territorial connector between the Houthi-controlled north and the south, Dhalea remains a volatile and active line of contact.

What do we know about the latest humanitarian situation in Yemen?

The United Nations said on Friday that nearly 46,000 people have been displaced in Yemen since fighting escalated earlier this week, though the figure is likely higher, according to Abdusattor Esoev, chief of the International Organization for Migration in Yemen.

Esoev told Al Jazeera that the fall of Mocha, where the UN maintained a strong presence, had made it more difficult for aid agencies to reach people in need.

More than 2,000 Yemenis have arrived in Djibouti in the past 24 hours amid fierce fighting, with at least 76,000 people displaced since July.

What to know about the fighting between the Houthis and Saudi Arabia?

The Houthis have launched missile and drone attacks on southern Saudi Arabia in recent days.

On Tuesday, the group struck civilian and economic facilities in the Saudi cities of Abha, Khamis Mushait, Jazan and Najran, wounding 73 people, including women and children.

The attacks on the kingdom are part of a rapid escalation in Yemen’s long-running conflict, which reignited in July after roughly four years of relative calm under a UN-brokered truce.

On Sunday, the Houthis also claimed they had struck a Saudi military base in Sharurah, in the southern Najran province, using ballistic missiles and drones.

Houthi military spokesperson Yahya Saree said in a post on X that the attack hit “weapons depots and command and control centres” and that the targeted sites were “managing the aggression against our nation and people”.

Saree, who did not state when the attack took place, warned Saudi Arabia that further military actions would prompt larger, more intense attacks deeper inside Saudi territory.

Earlier, Saree had said that Saudi warplanes had launched 129 air raids over the past 48 hours, “targeting the governorates of Taiz, Marib, Hodeidah, al-Jawf, Saada, Amran, and Hajjah”.

He added that F-15 and Typhoon aircraft were used in the attacks and took off from bases in Saudi Arabia’s Khamis Mushait and Taif.

“These attacks on our people will not go unanswered, God willing,” he added.

On Sunday, Saudi Civil Defence said two people were wounded and a mosque and several buildings were damaged after a projectile fired by the Houthi fighters struck Saudi Arabia’s southern Jazan region.

Several vehicles were also damaged by the projectile that landed in Jazan’s al-Tuwal governorate on Saturday, it added.

A Civil Defence spokesperson called the attacks on civilian objects a “flagrant violation of international humanitarian law”, adding that established emergency procedures had been implemented.

Al-Basha, the analyst, told Al Jazeera that Saudi Arabia is facing growing pressure to launch a larger military operation against the Houthis, but any campaign would still depend heavily on forces fighting on the ground.

He noted that while the Saudi-led coalition has not officially acknowledged carrying out air attacks, “it’s safe to say that the Saudis are providing air support.”

But he said air power alone would not be enough.

“Aircraft and firepower could suppress, could slow down the advance of the Houthis, but it’s the forces on the ground that will make a difference,” he said.

Al-Basha said he also did not expect the United States to join the fighting directly.

“We are not at war with the Houthis. The Houthis are not at war with us,” he said, referring to the US position, adding that Washington could still support any future Saudi operation with “intelligence, refuelling, logistics and military advice”.

But he added that “the Houthis will do whatever they can do to take over the whole of the country.”

Al-Basha said he did not expect either side to collapse quickly, predicting instead “a protracted conflict” more similar to Sudan, with both sides eventually forced to negotiate.

What has Iran said?

Iranian authorities and state media have praised the Houthis’ capture of Yemen’s Red Sea coast, which some see as giving Tehran more leverage against the US.

“The victories of Yemen’s Ansar Allah in the western coast is a narrative of a divine triumph and the fruit of years of steadfastness in the most difficult of battlefields,” Hossein Mohebbi, spokesman of the Islamic Revolutionary Guard Corps (IRGC), wrote on X on Saturday.

Mohammad Bagher Ghalibaf, Iranian parliament speaker, reposted a comment made by slain Supreme Leader Ayatollah Ali Khamenei in 2024, saying the “resistance” of the Houthis will inevitably lead to victory.

“The brave Yemeni people will certainly triumph, by permission of God Almighty,” Ghalibaf added on Thursday, in Arabic.

The “grand victory” of the Houthis once again proved that “security is not a commodity that can be bought,” added Mohammad Mokhber, an adviser to Iran’s Supreme Leader Mojtaba Khamenei.

But Iran’s diplomatic apparatus did not immediately link the Houthi advances with the current fight against the US.

As has often been the case, Iran’s Ministry of Foreign Affairs insisted that the Houthis make their decisions independent of Tehran, with their own interests at heart, including ending Saudi Arabia’s blockade on Yemen.

The Iranian Foreign Ministry also called for an end to the Saudi siege on Houthi-controlled areas, an immediate return to negotiations between the group and Riyadh, and respect for Yemen’s sovereignty and territorial integrity.

The ministry pushed back on the idea that the Houthis act merely as a proxy for Tehran.

“What is happening now in Yemen is the result of the Yemenis losing patience,” Foreign Ministry spokesman Esmaeil Baghaei told state television on Friday night.

“It is not fair to ignore the fact that they were under a cruel blockade for years, and concluded that the United Nations and regional mechanisms could not resolve the issues.”

Who are the key players?

Yemen’s more than a decade-long civil war has flared up once again after the Houthi armed group launched an offensive in several locations against Saudi-backed government forces earlier this month. The conflict has already spilled over beyond the country’s borders, with the Houthis carrying out attacks in southern Saudi Arabia, including oil facilities. Dozens of people were wounded in those attacks.

The renewed hostilities are the most serious since a UN-brokered truce halted large-scale fighting in 2022, after eight years of a full-blown conflict that killed tens of thousands of people in one of the world’s poorest countries.

The key players include:

The Houthis

The Houthis took over vast swaths of Yemen in 2014. Months later, Saudi Arabia intervened militarily in support of the internationally backed government.

The Iran-backed group continues to control northern Yemen, including the capital, Sanaa. It is seen as part of a regional alliance known as the “axis of resistance” backed by Iran. The group nevertheless has its own base, its own interests – and its own ambitions.

Presidential Leadership Council (PLC)

The PLC was established in 2022 when the former president, Abd-Rabbu Mansour Hadi, formally transferred his powers to the new eight-member body. It represents the internationally recognised government of Yemen.

Its membership is drawn from a mix of northern and southern politicians and military-linked leaders in a bid to unite major anti-Houthi forces under one roof.

The PLC is backed by Saudi Arabia and the alliance that Riyadh leads.

Islah Party

The Yemeni Congregation for Reform, better known as Islah, is a Sunni Islamist movement with historic ties to the Muslim Brotherhood. It is a faction within the recognised PLC-led government but has long had an independent identity. Its major stronghold has long been Marib, the country’s sole gas-producing region with one of its largest oilfields.

National Resistance Forces

The National Resistance Forces is a government-aligned military faction led by Tareq Saleh, nephew of the late former President Ali Abdullah Saleh.

The force has maintained ties to Saudi Arabia and, like the Islah party, is part of the PLC. It aims for a unified Yemen, positioning itself as a counterweight to both the Houthis and southern secessionists.

Saudi Arabia

Riyadh entered the Yemen war when it led a military coalition against the Houthis in March 2015, seeking to restore the government of then-President Abd-Rabbu Mansour Hadi. Back then, Saudi Arabia and Iran were at the peak of a regional competition, both deeply distrusting each other. Saudi Arabia saw the control of its southern border by the Iran-aligned Houthis as a security threat.

This was before a China-brokered rapprochement between Saudi Arabia and Iran in 2023.