Iranian naval forces have seized a foreign-registered ship they said was smuggling fuel in the Gulf and arrested its crew, state media reported on Saturday.

"A foreign vessel carrying 757,000 litres of smuggled fuel has been seized," the state broadcaster's website quoted a commander of the Revolutionary Guards maritime forces as saying.

"The seven crew members, who are foreign nationals, have been arrested and handed over to judicial authorities," General Ramazan Zirahi added, without specifying their nationalities.

It is not known when the vessel was seized, or what flag it sailed under.

"The vessel, that intended to transport and deliver its cargo of fuel to other countries, was seized 60 miles off the coast of Iran," Zirahi said, but did not say whether the cargo originated in the Islamic republic.

Iran has one of the cheapest petrol prices worldwide, which could make smuggling to other countries a lucrative business.

Zirahi noted that the ship was carrying "gasoline", and said the fight against smuggling, "especially organised fuel smuggling, is one of the priorities of the IRGC's naval forces to support national production and the dynamism of the economy".

In recent months Iran has announced several operations targeting fuel smuggling in the Gulf, where a large amount of the world's oil is produced and shipped.