Security sources: Iranian-backed forces seized tanker in A. Gulf

Earlier on Tuesday Britain's maritime trade agency reported a "potential hijack" was unfolding off the Gulf region.

Iran denied involvement in that suspected drone strike and said it would respond to any threat against its security.

Iran and Israel, longtime adversaries, have exchanged accusations of carrying out attacks on each other's vessels in recent months.

The United States and Britain said on Sunday they would work with their allies to respond to last week's attack on the Mercer Street, a Liberian-flagged, Japanese-owned petroleum product tanker managed by Israeli-owned Zodiac Maritime.