Attacks on commercial shipping in the Gulf have intensified as the war between the US and Iran escalated, raising concerns about disruptions to energy supplies from one of the world’s most critical oil transit routes.

On Thursday alone, several tankers came under attack in Gulf waters even as Iranian drones entered ​Azerbaijan, threatening to spread the crisis to more oil producers in the region, reported Reuters.

A Bahamas-flagged crude tanker anchored near Iraq’s Khor Al Zubair port was targeted by an Iranian remote-controlled boat carrying explosives, according to initial assessments. A second tanker at anchor off Kuwait was damaged by a large explosion on its port side and was reported to be taking on water while spilling oil.

The latest incidents bring to nine the number of vessels attacked since hostilities between the US, Israel and Iran began on Saturday.

Iran also launched a new wave of missiles at Israel early on Thursday and sent drones into neighbouring Azerbaijan, injuring four people and raising fears that the conflict could spread to additional oil-producing countries in the region, said media reports.

The escalation comes after efforts in Washington to halt US attacks were blocked and as the son of Iran’s slain supreme leader emerged as a leading contender to succeed him, signalling that Tehran is unlikely to retreat under mounting pressure.

Shipping activity in the region has slowed sharply. Around 200 vessels — including oil tankers, liquefied natural gas carriers and cargo ships — were anchored in open waters near major Gulf producers, according to Reuters estimates based on MarineTraffic tracking data. Hundreds more ships remained outside the Strait of Hormuz, unable to reach regional ports.

President Donald Trump offered US Navy escorts and insurance in a bid to restart shipping flows and curtail ​energy prices. Insurance market Lloyd's of London said on Thursday it is engaging with the US government on a plan.

BP evacuated foreign staff from Iraq's ​Rumaila oil field after two unidentified drones landed inside the field, Iraqi oil sources said. Iraq has cut its oil production by nearly 1.5 million barrels a day as ‌it ⁠ran out of storage and was unable to load tankers, stated senior officials.

A refinery in Kuwait shut down and another reduced its processing rate. A third refinery in Bahrain also cut its output.

Oil prices on the rise 

Oil prices extended their rally on Thursday, with Brent climbing 3% and WTI rising 4%. They have both jumped 16% since the war started on Saturday, as U.S.-Israeli strikes on Iran disrupted Middle East supplies.

A benchmark European gas price gained around 3% on Thursday. It has ​surged nearly 60% so far this week.

Russian ​President Vladimir Putin said his ⁠country could halt gas supplies to Europe right now, amid the spike in energy prices from the Iran crisis.

Qatar, which provides 20% of the world's LNG supply, halted gas production earlier this week due to the conflict. Other major ​producers such as the U.S. and Australia have little spare capacity to offset this lost supply, according to ​Reuters calculations and industry ⁠analysts.