North Korea has fired a ballistic missile into waters off its east coast, just days before the United States and South Korea begin annual military drills known as the Ulchi Freedom Shield exercises in the region.

The launch at 6am on Wednesday (21:00 GMT) was the second reported North Korean missile test in less than a week amid tensions over Pyongyang’s growing military ties with Russia and concerns about its expanding weapons programme.

North Korea has not immediately commented on the latest launch but has repeatedly condemned annual US-South Korea drills in its neighbourhood.

Washington and Seoul say the exercises are defensive and designed to prepare their forces for potential North Korean attacks.

Here is what you need to know:

What has happened?

South Korea’s Joint Chiefs of Staff said a ballistic missile was launched from the Wonsan area, where a port city and naval base are located in Kangwon Province, North Korea, at about 6am local time (21:00 GMT). It flew for more than 700km (435 miles) before landing in waters between the Korean Peninsula and Japan.

The launch was also detected by Japanese authorities, which reported that the missile had fallen outside Japan’s exclusive economic zone.

South Korea’s Office of National Security convened an emergency meeting and expressed concern over North Korea’s continued ballistic missile launches. It urged Pyongyang to halt provocations which violate UN Security ⁠⁠⁠⁠Council resolutions.

The launch came six days after North Korea fired another ballistic missile from the same area. Pyongyang did not confirm that earlier launch either, which Seoul, Washington and Tokyo all said they detected on August 6.

Why did North Korea fire a missile into the sea?

North Korea has provided no explanation for the missile launch. However, the timing strongly suggests it was partly intended as a warning ahead of the US-South Korea military exercises, analysts say.

North Korea has previously condemned annual joint drills by Washington and Seoul, which it regards as rehearsals for an invasion. The US and South Korea say these are defensive exercises only, designed to prepare for potential attacks by Pyongyang.

North Korea has also previously responded to major US-South Korea exercises with missile tests and threatening rhetoric.

Lim Eul-chul, a North Korea expert at Kyungnam University in South Korea’s South Gyeongsang Province, told AFP that Pyongyang has “never simply let” a South Korea-US joint military exercise pass without a response.

He added that the latest launch can be seen as a message that North Korea is closely watching the upcoming drills and could take further action if it considers it necessary.

Where are the US and South Korea holding joint military drills?

The Ulchi Freedom Shield exercises will take place in South Korea from August 17-27 on and around the Korean Peninsula.

Drills will involve about 18,000 South Korean troops and personnel from the US contingent of roughly 28,500 troops stationed in South Korea.

Why are these drills taking place?

The US and South Korea say their military training is for defensive purposes and is necessary because North Korea possesses nuclear weapons and continues to develop missiles and other military capabilities.

The drills are specifically aimed at countering Pyongyang’s evolving nuclear and weapons capabilities.

This year’s exercises also take into account North Korea’s growing military cooperation with Russia. North Korea has also reportedly sent thousands of soldiers to assist Russia in the war against Ukraine.

North Korean soldiers have “taken those lessons they learned there and brought them back to North Korea”, Colonel Ryan Donald, spokesman for the US and South Korean Combined Forces Command, said on Monday.

How regular are North Korea’s missile tests?

South Korea says this launch is the North’s 11th suspected ballistic missile test this year.

Hong Min, a senior researcher at the Korea Institute for National Unification, told Reuters that the missile test was likely to be part of North Korea’s existing weapons-development programme.

However, Min added that choosing when to conduct such a test was itself a political decision, suggesting the timing may have been selected to send a message ahead of the exercises.

Multiple UN Security Council resolutions ban North Korea from launching ballistic missiles.

What is the context behind all this?

The latest missile launch is part of a broader increase in North Korea’s weapons testing.

Pyongyang has expanded its ballistic missile and other weapons programmes since diplomacy between North Korean leader Kim Jong Un and US President Donald Trump broke down during Trump’s first term in the White House in 2019.

The tests also come amid worsening regional tensions. South Korea and Japan condemned Wednesday’s missile launch, while Seoul said it remained ready to respond to any provocation alongside the United States.

Pyongyang has also criticised South Korea’s plans for nuclear-powered submarines and accused Japan of moving towards greater militarisation.

Earlier this month, Kim Yo Jong, sister of North Korean leader Kim Jong Un, warned that Pyongyang would adopt “additional military options” after Japan test-fired a United States-made Tomahawk cruise missile.

In turn, South Korea and the US have accused North Korea of playing a more active role in the Russian invasion of Ukraine.

Ukrainian President Volodymyr Zelenskyy claimed on Tuesday that Moscow had used a North Korean ballistic missile during an attack that killed 12 workers at a Ukrainian steel plant in the southeastern city of Zaporizhzhia.