Merchant shipping heading through Middle Eastern waters has been placed back on high alert over fears Iran may retaliate to American drone strikes earlier today that killed a top Iranian general.

Iran’s most powerful military commander, General Qasem Soleimani, was killed by a US air strike in Iraq at around 1am this morning.

Iran’s Supreme Leader Ayatollah Ali Khamenei said today “severe revenge awaits the criminals” behind the attack.

For many months last year, tensions between Iran and the west were a constant in the news with attacks on a string of tankers, ships kidnapped and insurance premiums soaring.

Commenting on today’s drone strike, maritime security consultant Lars Bergqvist told Splash, “Certainly this may affect shipping, and the Iranians may threaten to close Strait of Hormuz, which is a soft spot.”

Bergqvist said that the guidelines for merchant ships heading to the area, already in place for much of the last 12 months, need to be reviewed and implemented.

Samir Madani, founder of TankerTrackers.com and a close watcher of shipments into and around Iran, said via Twitter that he was convinced Iran would not try to shut down the Strait of Hormuz as a result of today’s strike.

“China is the region’s biggest client, and they just had a joint navy exercise a few days ago. Oil will continue to flow. If price rises, then even more might actually flow,” Madani predicted.

Global oil prices soared more than 4% in the wake of the strike.