DUBAI (Reuters) - Four commercial vessels were targeted by “sabotage operations” near the territorial waters of the United Arab Emirates without causing casualties, the foreign ministry said on Sunday, without giving details of the nature of the sabotage.

The incident occurred near the UAE emirate of Fujairah, one of the world’s largest bunkering hubs which lies just outside the Strait of Hormuz, the ministry said in a statement.

Trading and industry sources said operations at Fujairah port ran smoothly on Sunday.

The strait, a vital global oil and gas shipping route, separates the Gulf states and Iran, which has been embroiled in an escalating war of words with the United States over U.S. sanctions and the U.S. military’s regional presence.

“Subjecting commercial vessels to sabotage operations and threatening the lives of their crew is considered a dangerous development,” according to the statement that was carried by state news agency WAM.

The statement, which did not identify the vessels beyond saying they were of various nationalities, said the incident did not result in spills. The UAE did not blame any country or other party for the operation.

Regional tensions have increased, with Washington saying it was sending a U.S. aircraft carrier and other forces to the Middle East due to what it said were Iranian threats, while Tehran has called the U.S. military presence “a target” rather than a threat.

The U.S. Navy’s Bahrain-based Fifth Fleet told Reuters it was aware of the UAE report but referred queries to the UAE authorities.

SECURITY MEASURES

A senior Iranian lawmaker and head of parliament’s national security committee, Heshmatollah Falahatpisheh, said on Sunday that reports of “explosions” near Fujairah port showed the security of Gulf states was fragile.

The government of Fujairah, one of the seven emirates that make up the UAE and which has a coastline on the Gulf of Oman, denied in a tweet media reports about blasts inside Fujairah port and said the facility was operating normally.

Fujairah’s statement did not identify media outlets that had published reports about any blasts but Iran’s Press TV website cited a Lebanese broadcaster, Mayadeen, saying seven oil tankers had been attacked in the port.

The UAE ministry statement, which denied any incident had taken place inside the port, said the government had taken all necessary measures and launched an investigation in coordination with international authorities.

“The international community should carry out its responsibilities to prevent any parties trying to harm maritime security and safety, which would be considered a threat to international safety and security,” it added.

The administration of U.S. President Donald Trump has been ratcheting up pressure on Iran with sanctions since Washington withdrew a year ago from a 2015 international nuclear deal between Tehran and world powers.

Washington tightened sanctions on Iran this month, eliminating waivers that had allowed some countries to buy its oil, saying it wanted to cut Tehran’s crude exports to zero. Iran has said it will not let its oil exports by halted.

The UAE’s Gulf Arab ally Bahrain described the Fujairah incident as “a dangerous criminal act”.