Saudi Arabia has said two of its oil tankers were “sabotaged” off the coast of the United Arab Emirates in attacks causing "significant damage".
Four ships were targeted on Sunday, according to the UAE, but there have been no casualties reported off the coast of the port city of Fujairah.
The announcement came just hours after Iranian and Lebanese media outlets aired false reports of explosions at the city's port.
Saudi Arabia did not identify the vessels involved, nor did it say who it suspected of carrying out the alleged sabotage.
Despite the lack of detail on the incident, Minister of Energy Khalid al-Falih reports one of the vessels was on its way to load Saudi oil to take to the US.
The US recently warned ships that "Iran or its proxies" could be targeting maritime traffic in the region and is deploying an aircraft carrier and B-52 bombers to counter alleged threats from Tehran.
Shortly after the Saudi announcement, Iran's Foreign Ministry called for further clarification about what exactly happened with the Saudi tankers.
The ministry's spokesman, Abbas Mousavi, was quoted by the official IRNA news agency as saying there should be more information about the incident.
Mr Mousavi also warned against any "conspiracy orchestrated by ill-wishers" and "adventurism by foreigners" to undermine the maritime region's stability and security.
Tensions have risen in the year since US president Donald Trump withdrew the US from the 2015 nuclear deal between Iran and world powers, restoring sanctions that have crippled Iran's economy.
Last week, Iran warned it would begin enriching uranium at higher levels in 60 days if world powers failed to negotiate new terms for the deal.
In his statement, Mr al-Falih said the attacks on the two tankers happened at 6am on Sunday.
"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," Mr al-Falih said.
"Fortunately, the attack didn't lead to any casualties or oil spill; however, it caused significant damage to the structures of the two vessels."
Underling the regional risk, the general-secretary of the six-nation Gulf Cooperation Council described the alleged sabotage as a "serious escalation" in an overnight statement.
"Such irresponsible acts will increase tension and conflicts in the region and expose its peoples to great danger," Abdullatif bin Rashid al-Zayani said.
Bahrain, Egypt and Yemen's internationally recognised government similarly condemned the alleged sabotage.
A statement on Sunday from the UAE's Foreign Ministry put the ships near the country's territorial waters in the Gulf of Oman, east of the port of Fujairah.
It said it was investigating "in cooperation with local and international bodies".
It said there were "no injuries or fatalities on board the vessels" and "no spillage of harmful chemicals or fuel".
The US Navy's 5th Fleet, which oversees the region, did not immediately offer comment.
Emirati officials declined to answer questions from The Associated Press, saying their investigation is ongoing.
Earlier on Sunday, Lebanon's pro-Iran satellite channel Al-Mayadeen, quoting "Gulf sources", falsely reported that a series of explosions had struck Fujairah's port.
State and semi-official media in Iran picked up the report from Al-Mayadeen, which later published the names of vessels it claimed were involved.
The AP, after speaking to Emirati officials and local witnesses, found the report about explosions at the port to be unsubstantiated.
Fujairah's port is about 85 miles south of the Strait of Hormuz, the narrow mouth of the Persian Gulf through which a third of all oil at sea is traded.
The facility handles oil for bunkering and shipping, as well as general and bulk cargo.
It is seen as strategically located, serving shipping routes in the Persian Gulf, the Indian subcontinent and Africa.