The United States has talked of sharing intelligence and coordination to help other nations protect their commercial vessels passing through the gulf. But Washington has made clear that its role would be limited and that other nations must help shoulder the burden.

The recording may bolster British claims about the location of the ship at the moment of its capture, though it is possible that the naval officer was not speaking accurately about its location. The owner of the tanker, Stena Bulk, has said that it was in international waters at the time it was seized, and on Saturday, British officials said the ship was in Omani waters.

Iran has said that the tanker was sailing through Iranian waters, and has offered different explanations for its seizure, including that it had been polluting the gulf or had collided with an Iranian fishing boat.

Iranian officials, however, have also described the seizure as retribution for the British impounding of an Iranian tanker off the coast of Gibraltar on July 4. Britain has said that it stopped that tanker on suspicion that it had been violating a European Union embargo on the delivery of oil to Syria.

Iran has called that seizure an act of piracy directed by Washington as part of a pressure campaign against Tehran.

Britain’s foreign secretary, Jeremy Hunt, this weekend called the exchange a tanker “tit for tat.” But it is also part of a larger confrontation between Washington and Tehran over a 2015 agreement between world powers and Iran to limit the country’s nuclear program, which Western governments have feared might enable Iran to produce a nuclear weapon.

President Trump last year pulled the United States out of the agreement, vowing to force Iran to submit to more onerous and permanent restrictions on its conventional military and regional policies, as well as on its nuclear program.