WASHINGTON: The United States and its allies are discussing plans to provide naval escorts for oil tankers through the Gulf, a top US general said Thursday after Iranian military vessels menaced a British tanker.

General Mark Milley, nominated to become the chairman of the Joint Chiefs of Staff, told a Senate hearing that the US has a "crucial role" in enforcing freedom of navigation in the Gulf.

He said the US was attempting to put together a coalition "in terms of providing military escort, naval escort to commercial shipping," he said.

"I think that that will be developing over the next couple weeks."

Milley, currently chief of staff of the army, confirmed less specific remarks by current Joint Chiefs Chairman General Joseph Dunford earlier this week.

Dunford told media that the Pentagon was working to identify possible partners in an effort to protect navigation in the Straits of Hormuz and Bab al-Mandab on either side of the Arabian peninsula where much of the world's crude oil traffic passes.

Milley's remarks came after London said Thursday that armed Iranian boats tried to block a supertanker before being warned off by a British warship in a dramatic escalation in the Gulf.

The British defense ministry said three Iranian boats tried to "impede the passage" of the British Heritage, a 274-meter (899-foot) tanker owned by BP that can carry a million barrels of oil.

"We are concerned by this action and continue to urge the Iranian authorities to de-escalate the situation in the region," a Downing Street spokesman said.

Iran's Revolutionary Guards denied involvement but also cautioned both the United States and Britain that they would "strongly regret" the British detention of a tanker carrying Iranian crude oil off Gibraltar last week.