A Qatari liquefied natural gas carrier was attacked on Monday evening in the Strait of Hormuz, an incident that tests the ongoing peace negotiations between the United States and Iran.

The UK Maritime Trade Operations reported that a vessel caught fire after being struck by an unidentified projectile near the Omani coast at the entrance to the strait. Three informed sources identified the targeted ship as the Al Rekayyat, a fully laden LNG carrier owned by QatarEnergy.

This attack is the latest in a series of sporadic assaults on commercial vessels transiting the Gulf, occurring as the US and Iran attempt to reach an agreement on reopening the contentious waterway. Approximately one-fifth of the world's oil and gas is transported through this strait.

Two sources close to the situation stated that another vessel was also attacked overnight. One of these sources indicated it was a Saudi crude oil tanker, though the circumstances remain under investigation.

A US official stated that Iran fired at least two missiles at merchant ships passing through the strait.

The attack took place as Iran was holding several days of commemorative activities mourning its slain supreme leader, Ayatollah Ali Khamenei, who was killed in the early stages of the conflict by a US-Israeli strike.

Maritime traffic through the strait had seen a recovery following a US-Iran memorandum of understanding signed three weeks ago, but volumes remain significantly below pre-war levels. As part of the deal, Iran agreed not to charge transit fees for 60 days and to clear mines from the main shipping lanes. However, Iran has since insisted that vessels should follow a route closer to the Iranian coast rather than one further south, near Oman.

Data from Lloyd's List Intelligence shows that after an initial surge, the number of vessels attempting the passage has declined. The agency reported 211 ships transited the waterway in the week to July 5, down from 262 the previous week.

Ship-tracking data indicated that another Qatari LNG carrier, the Al Areesh, was heading towards the strait but turned back early Tuesday morning.

Pakistani officials stated that the country has recently been forced back into the more expensive spot market, driving up costs during an intense summer heatwave.

Pakistan, which has been conducting behind-the-scenes mediation between the US and Iran, separately reached an agreement with Tehran's Revolutionary Guards in May to secure the passage of its Qatari LNG supplies through the strait.

A government official in Islamabad said the Al Areesh turned back because "another ship was attacked in the strait." This official, involved in procuring gas from Qatar, noted that Qatar provides nearly all of Pakistan's LNG supply. The official added that Islamabad is negotiating with Iran and Qatar to obtain "assurances" that the Al Areesh will not be attacked on a second attempt to transit the strait.

According to two informed sources and ship-tracking data, several other vessels turned back over the weekend, while two others altered their course from the Omani route to one nearer the Iranian coast.

The United States has been providing air cover for some vessels transiting via the Omani coastline.

Two informed sources also reported that Iranian patrol boats were present in the strait on Saturday.