Two explosive-laden, unmanned ‌boats rammed the Safesea Vishnu tanker in an Iraqi seaport on Wednesday, sparking a fiery blast that engulfed the vessel’s port side in flames and left the crew only seconds to react, according to an early assessment conducted by the vessel’s ​US owner and operator.

“After speaking to the surviving crew members, the attack appears to have ​been deliberate and calculated,” New Jersey-based Safesea Group said in a statement.

At least ⁠16 tankers and other vessels have come under attack in the Gulf during the US-Israeli war with Iran. ​Hundreds more have dropped anchor due to Tehran’s threat to attack vessels in or near the Strait ​of Hormuz, which is used to transport roughly one-fifth of the world’s oil.

The Marshall Islands-flagged Safesea Vishnu was anchored at the Iraqi port of Khor Al Zubair and engaged in ship-to-ship loading of 53,000 metric tons of naphtha at ​the time of the attack.

The vessel’s 28 crew members, without time to deploy lifeboats, jumped into ​the water to escape the burning vessel.

One died; the remaining 27 crew are safe and receiving assistance from ‌the Embassy ⁠of India in Iraq, Safesea said.

The tanker is reported to be listing in the water, and a salvage team has been sent to stabilise the ship and make sure the surrounding marine environment is safe.

The attack must serve as a wake-up call for governments, maritime authorities, and the international community, ​Safesea said.

“Commercial shipping lanes ​cannot become battle zones,” ⁠it said.

The Malta-flagged Zefyros was the other ship involved in the transfer.

A projectile struck that vessel during the Wednesday night assault, its Greece-based manager ​said on Thursday. All 23 crew on the Zefyros were safely evacuated.

Some 20,000 ​seafarers aboard ⁠vessels operating in the region face “a dangerous and highly uncertain security situation,” according to the World Shipping Council.

US President Donald Trump has said the United States is prepared to escort tankers through the Strait of Hormuz when ⁠necessary, ​but so far the US navy has refused near-daily requests ​from the shipping industry for military escorts since the start of the war on Iran, saying the risk of attacks is too ​high for now, according to sources familiar with the matter.