Fresh attacks on commercial vessels near the Strait of Hormuz and off the Yemeni coast have heightened fears over the safety of Gulf shipping.

At the same time, Saudi air defences intercepted more drones over the capital, Riyadh, and other regions.

The United Kingdom Maritime Trade Operations (UKMTO) said a tugboat near the Strait of Hormuz was hit by two projectiles. It also reported that one tanker was struck by an RPG fired from a small boat.

In a separate incident, armed men fired on a tanker off the Yemeni port city of Al Mukalla. Reports describe the vessel as a liquefied natural gas carrier. At least four tankers have been reported hit around Hormuz since Friday.

The navy of Iran’s Islamic Revolutionary Guard Corps (IRGC) declared the strait “closed”. It claimed one of the tankers, carrying about two million barrels of crude, had taken an “unauthorised” route. Iranian state television aired footage it said showed a tanker explosion in the waterway. The footage has not been independently verified, and the exact cause of the blasts remains unclear.

The incidents come as UKMTO data shows attacks on ships in or near the strait at a record weekly high since the war began in February. At least 10 vessels have been targeted in the past week, and 23 attacks have been logged since the start of October, nearly double the usual rate.

The US military says it has blocked billions of dollars’ worth of Iranian oil exports under its naval blockade of Iranian ports. Tehran says the strait was closed because Washington reneged on its commitments.

On the Saudi front, the Riyadh-led coalition fighting Yemen’s Iran-backed Houthi rebels said it intercepted and destroyed four drones over the Riyadh, Eastern and Southern regions. Coalition spokesman Turki al-Malki confirmed the interceptions. The Saudi military also said two of its personnel were killed in a helicopter crash near the Yemen border.

Riyadh has accused Iran of encouraging the Houthis’ escalation, which Tehran denies. The Houthis have repeatedly hit Saudi energy facilities and Riyadh’s King Khalid International Airport, where at least 13 people were killed in an attack earlier this month. Iranian Foreign Minister Abbas Araghchi has said the next move rests with Washington, even as diplomatic efforts continue.