pFour commercial ships were targets of a “sabotage attack” off the United Arab Emirates (UAE) on Sunday, the country’s foreign affairs ministry has said.
The incident reportedly took place near Fujairah port, just outside the Strait of Hormuz, but caused no casualties.
Saudi Arabia confirmed that two Saudi oil tankers sustained “significant damage”.
Another vessel was Norwegian-registered, whilst the fourth was reportedly UAE-flagged.
Iran, which borders the strait, has called for a full investigation.
Tensions are high in the region. About a fifth of oil that is consumed globally passes through the area.
Last month, Iran threatened to “close” the Strait of Hormuz if it was prevented from using the waterway.
This followed a US decision to end exemptions from sanctions for major importers of Iranian oil.
The US has deployed warships to the region in recent days to counter what it called “clear indications” of threats from Iran to its forces and maritime traffic. Iran dismissed that allegation as nonsense.
A US military official told the BBC that, at the UAE’s request, America had send “a team of experienced investigators” to help determine the cause of the damage.
US Secretary of State, Mike Pompeo, made an unplanned visit to Brussels on Monday to discuss Iran with European foreign ministers.
Few details have been released about the incident, which is said to have taken place at about 06:00 (02:00 GMT) on Sunday within the UAE’s territorial waters in the Gulf of Oman, east of the emirate of Fujairah.
The UAE foreign ministry said on Sunday that it was investigating.
The ministry also denied as “baseless and unfounded” media reports of fires and explosions at Fujairah port, and insisted operations at the facility were normal.
On Monday morning, the official Saudi Press Agency quoted the country’s energy minister, Khalid al-Falih as saying two Saudi oil tankers had been among the ships targeted.
“One of the two vessels was on its way to be loaded with Saudi crude oil from the port of Ras Tanura, to be delivered to Saudi Aramco’s customers in the United States,” he added.
Industry sources told the BBC that the Saudi tankers affected were the Amjad and Al Marzoqah.
Saudi TV has shown images of the damaged Saudi ships, and a picture released by the UAE shows a Norwegian-flagged vessel, Andrea Victory, with damage to its hull.