Iran's Revolutionary Guards on Saturday seized a container ship "related to the Zionist regime (Israel) in the Gulf," state media reported, as tensions soar in the region.

"A container ship named 'MCS Aries' was seized by the Sepah (Guards) Navy Special Forces by carrying out a heliborne operation," IRNA state news agency reported.

It added that the operation took place "near the Strait of Hormuz", a waterway vital to world trade, and "this ship has now been directed towards the territorial waters" of Iran.

The Iranian report came after two maritime security agencies said "regional authorities" had seized a vessel off the coast of the United Arab Emirates.

"Vessel reported to have been seized by regional authorities" off the coast of Fujairah, the Royal Navy's United Kingdom Maritime Trade Operations agency said, without providing further details.

Security firm Ambrey said it "observed still footage of at least three individuals fast-roping from a helicopter onto what appeared to be a container ship".

Iran's Revolutionary Guards "have previously used this method of boarding while seizing vessels in the Strait of Hormuz", Ambrey added.

Portuguese flag

Vessel tracking websites, vesselfinder.com and marinetraffic.com, say MSC Aries is a Portuguese-flagged container ship. Both sites give its last reported position as in the Gulf.

The United States on Friday said it was sending military reinforcements to the region, after Iran vowed retaliation for a deadly strike on the consular section of its Damascus embassy in Syria almost two weeks ago.

United States President Joe Biden on Friday said he expected Iran to strike arch-foe Israel, which Tehran blamed for the consular attack, "sooner rather than later".

The April 1 strike killed at least seven members of Iran's Revolutionary Guards, including two generals.

The surging tensions come against the backdrop of the six-month war waged by Israel against Iran-backed Hamas Palestinian militants in Gaza.

The conflict has since drawn in regional actors including Iran-backed groups in Yemen, Lebanon, Syria and Iraq.

Yemen's Iran-backed Huthi rebels have carried out dozens of missile and drone attacks against shipping in the Red Sea area, and in November seized an Israel-linked cargo vessel, the Galaxy Leader. The crew are still being held.

Tehran has supported Hamas, but repeatedly denied direct involvement in the October 7 Hamas attack on Israel that started the war.

Iran in January seized a ship off the coast of Oman in retaliation for what it described as American "theft" of its oil from the same tanker.

Iran's navy had boarded the Greek-owned St Nikolas before later releasing the crew members.

Much of the world's oil which is shipped by sea passes through the Strait of Hormuz, where Iran said the latest incident occurred.