DUBAI, United Arab Emirates (AP) — A ship has been struck by an explosion Friday near the strategic mouth of the Persian Gulf, American and British military officials said.

The unexplained blast comes amid heightened tensions between Iran and the U.S. over Tehran's nuclear program. The site of the blast, the Gulf of Oman, saw a series of explosions in 2019 that the U.S. Navy blamed on Iran, something Tehran denied.

Details of the blast remained unclear. The United Kingdom Maritime Trade Operations, which is run by the British navy, says the crew and the vessel is safe after the explosion. The vessel, which it did not name, is now heading to port.

The U.S. Navy's Bahrain-based 5th Fleet was “aware and monitoring” the situation, Cmdr. Rebecca Rebarich told The Associated Press. She declined to immediately comment further.

The British maritime organization gave the ship's last position off the coast of Muscat, the capital of Oman.

While the circumstances of the explosion remain unclear, Dryad Global, a maritime intelligence firm, said it was very possible the blast stemmed from “asymmetric activity by Iranian military,” which it said would be “commensurate” with heightened regional tensions.

As Iran seeks to pressure the United States to lift sanctions and return to the 2015 atomic accord, the country may seek “to exercise forceful diplomacy through military means,” the Dryad report said.

Iran did not immediately acknowledge the incident.

In the summer of 2019, against the backdrop of steeply rising tensions between Iran and administration of former President Donald Trump, the U.S. military blamed Iran for suspected attacks on two oil tankers near the Strait of Hormuz, one of the world's most strategic shipping lanes.

The explosions came after the U.S. attributed a series of confrontations in the region to Iran, including the use of limpet mines — designed to be attached magnetically to a ship’s hull — to attack four oil tankers off the nearby Emirati port of Fujairah, and the bombing of an oil pipeline in Saudi Arabia by Iranian-backed fighters.

Tensions between the nations escalated after Trump's unilateral withdrawal from the 2015 nuclear accord and reimposition of harsh sanctions on Iran. In response, Iran has gradually and publicly breached the nuclear deal with world powers to create leverage over Washington to return to the deal, which saw Tehran agree to limit its enrichment of uranium in exchange for the lifting of crippling sanctions.