Shipping in the Strait of Hormuz has plunged amid renewed fighting between the United States and Iran, dealing a new blow to energy markets already reeling from the biggest supply disruption in history.

No large vessel has crossed the strait via the US-coordinated route while broadcasting their location since Tuesday, with traceable crossings via the Oman-hugging lane “effectively grinding to a halt”, Lloyd’s List Intelligence said on Thursday.

“Lloyd’s List Intelligence data shows no vessels above 10,000 dwt have transited the so-called Southern Highway with their AIS switched on since July 7, although at least two ships are believed to have crossed dark,” the maritime data company said, using the abbreviations for deadweight tonnage and automatic identification system, and US President Donald Trump’s nickname for the Omani shipping route.

Only five vessels were tracked crossing the strait on Wednesday, and early Thursday morning, maritime intelligence platform Windward said on Thursday afternoon, compared with 45 transits on Monday.

Roughly 130 vessels transited the strait, one of the world’s most critical energy chokepoints, daily before the start of the war in late February.

United Kingdom Maritime Trade Operations said in its latest threat assessment released on Thursday that traffic levels reflected the “cautious posture” of shipping lines amid an “elevated threat environment.”

“The great risk is that as the crisis prolongs and start-stop dynamics become the perceived norm, shipping may begin to make more sustained decision to prioritise other ports and routes,” John Bradford, executive director of the Yokosuka Council on Asia Pacific Studies, a non-profit organisation dedicated to the study of strategic and diplomatic issues in the region, told Al Jazeera.

“Iran has the ability to strike ships across the Persian Gulf, through the Strait of Hormuz, and out into the Gulf of Oman,” Bradford said.

“That exposes all regional shipping to risk.”

Iran reported multiple explosions in the south of the country on Thursday, following US strikes on dozens of Iranian targets on Wednesday and Tuesday.

A US official told Al Jazeera that US forces were not behind the latest attacks, which have yet to be claimed by a particular country or group.

Iranian officials and media earlier on Thursday said that Tehran’s forces had struck US military assets and other sites in Bahrain, Kuwait, Qatar, Jordan, and Iraq in retaliation for the US strikes, which Washington launched in response to multiple attacks on vessels in the Strait of Hormuz.

Despite the latest turmoil in the region and the Strait of Hormuz, oil prices largely held steady on Friday, following several days of gains.

Brent crude, the primary international benchmark, stood at $76.37 per barrel as of 02:30 GMT, practically unchanged from its settlement price on Thursday and down about 2 percent from Wednesday.

After returning to pre-war prices following Washington and Tehran’s signing of a memorandum of understanding on ending the war last month, Brent is up more than $4 a barrel compared with last week.

While the relative price stability reflects “confidence on the part of the market that the situation will stabilise” in the Middle East, the latest hostilities will exacerbate the upward pressure expected to build as oil inventories dwindle in the coming weeks, said Bart Melek, global head of commodity strategy at TD Securities in Toronto, Canada.

“With that, we see Brent moving $10-$15 higher into the summer, as inventories of oil and product wane, stressing supply chains,” Melek told Al Jazeera, referring to the three months up to August.

June Goh, senior oil market analyst at Sparta Commodities in Singapore, said that refined petroleum products, rather than crude oil, are facing the greatest price pressures.

“Diesel, in particular, is grappling both from the loss of supply from the Middle East refineries, and from Russian refineries facing relentless attacks by Ukrainian drones, leading to skyrocketing diesel prices beyond seasonal norms against crude,” Goh told Al Jazeera.

After the US benchmark S&P 500 index rose 0.8 percent overnight, Asian stock markets opened higher on Friday, with major gains in Japan, South Korea and Hong Kong.

Tokyo’s benchmark Nikkei 225 rose 1.9 percent in morning trading, while Seoul’s Kospi jumped 3.6 percent.

In Hong Kong, the Hang Seng Index climbed 1.4 percent.