An explosion rocked a Greek-operated oil tanker docked at Saudi Arabia's port of Shuqaiq on Wednesday, Greek officials said, in an attack that a Riyadh-led military coalition blamed on Yemeni rebels.

The blast on the Maltese-flagged Agrari tanker follows a string of attacks by the Iran-linked rebels on Saudi oil infrastructure, highlighting the growing perils of a five-year military campaign led by the kingdom in Yemen.

The tanker was "attacked by an unknown source" while it was preparing to depart from the Red Sea port of Shuqaiq, its Greece-based operator TMS Tankers said, adding that no injuries were reported.

"The Agrari was struck about one meter above the waterline and has suffered a breach," TMS Tankers said in a statement.

"It has been confirmed that the crew are safe and there have been no injuries. No pollution has been reported."

An investigation was underway after Saudi authorities, including the coast guard, boarded the stricken vessel, it added.

There were 25 crew members onboard, including seven Greeks, according to an official at Greece's merchant marine ministry.

The incident occurred two days after Huthi rebels said they struck a plant operated by energy giant Saudi Aramco in the western city of Jeddah with a Quds-2 missile. The strike tore a hole in the roof of an oil tank, triggering an explosion and fire
The incident occurred two days after Huthi rebels said they struck a plant operated by energy giant Saudi Aramco in the western city of Jeddah with a Quds-2 missile. The strike tore a hole in the roof of an oil tank, triggering an explosion and fire AFP / FAYEZ NURELDINE

"The explosion happened around 0300 local time (0000 GMT), but the causes have not yet been identified," the ministry official said.

The tanker was carrying no cargo when the blast occurred, the ministry added, dispelling any fears of an oil spill.

The Saudi-led military coalition confirmed that a commercial vessel suffered minor damage during what it described as a foiled "terrorist act".

Without naming the vessel, it said the incident occurred when an explosives-laden boat launched by Yemen's Huthi rebels was intercepted and destroyed.

The commercial vessel was damaged by shrapnel from the "booby-trapped boat", the coalition was quoted as saying by the Saudi state-run Al-Ekhbariya television.

"The hostile acts of the Huthi militia threaten shipping lanes and global trade," the coalition said, without offering details.

A photo provided by Saudi Aramco on April 1, 2020, shows Aramco tankers being loaded with oil at an undisclosed sea location. An explosion rocked a Greek-operated tanker docked at Saudi Arabia's Red Sea port of Shuqaiq Wednesday, Greek officials said
A photo provided by Saudi Aramco on April 1, 2020, shows Aramco tankers being loaded with oil at an undisclosed sea location. An explosion rocked a Greek-operated tanker docked at Saudi Arabia's Red Sea port of Shuqaiq Wednesday, Greek officials said Saudi Aramco / -

Dryad Global, a London-based maritime intelligence firm, said that unnamed sources within the coalition indicated the blast was the "result of a Huthi-launched water-borne improvised explosive device (WBIED)".

"Vessels transiting the Red Sea area are reminded that regional conflicts exist whereby there is a realistic possibility that vessels of Saudi flag and those calling at southern Saudi ports are at moderate risk," Dryad Global said in a report.

There was no immediate reaction from the Huthis.

But Wednesday's incident comes as the Iran-backed rebels step up attacks on neighbouring Saudi Arabia in retaliation for the Saudi-led military campaign in Yemen.

On Monday, the Huthi rebels said they struck a plant operated by energy giant Saudi Aramco in the western city of Jeddah with a Quds-2 missile.

The strike, which underscores the vulnerability of Saudi Arabia's infrastructure and the rebel's advancing arsenal, tore a hole in the roof of an oil tank, triggering an explosion and fire.

Earlier this month, a fire broke out at a Saudi oil terminal off the southern province of Jizan after two explosives-laden boats launched by the rebels were intercepted by the coalition, according to the kingdom's energy ministry.

On Tuesday, the coalition said it had destroyed five naval mines planted by the Huthis in the southern Red Sea, saying such tactics posed a "serious threat to maritime security".

Saudi Arabia has repeatedly accused Iran of supplying sophisticated weapons to the Huthis, a charge Tehran denies.

Saudi Arabia is stuck in a military quagmire in Yemen, which has been locked in conflict since Huthi rebels took control of the capital Sanaa in 2014 and went on to seize much of the north.

The Saudi-led coalition intervened the following year to support the internationally recognised government, but the conflict that has shown no signs of abating.

Despite its superior firepower and military hardware, the coalition has struggled to oust the rebels from their northern strongholds, including Sanaa.

Tens of thousands of people, mostly civilians, have been killed and millions displaced in what the United Nations has called the world's worst humanitarian disaster.