The US issued a new warning early Monday to sailors over alleged "acts of sabotage" targeting ships off the coast of the United Arab Emirates amid heightened regional tensions between America and Iran.
The UAE's regional allies meanwhile condemned the reported sabotage Sunday of the four ships off the coast of Fujairah, which came just hours after Iranian and Lebanese media outlets aired false reports of explosions at the city's port.
Emirati officials have declined to elaborate on the nature of the sabotage or say who might have been responsible.
However, the reported incident comes as the US has warned ships that "Iran or its proxies" could be targeting maritime traffic in the region, and as America is deploying an aircraft carrier and B-52 bombers to the Persian Gulf to counter alleged threats from Tehran.
Tensions have risen in the year since President Donald Trump withdrew the United States from the 2015 nuclear deal between Iran and world powers, restoring American sanctions that have pushed Iran's economy into crisis.
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.
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 recognized government similarly condemned the alleged sabotage.
A statement 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 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.