Bahrain has ordered the expulsion of an Iranian diplomat for alleged links to a spy ring in fellow Gulf Arab state Kuwait, state media said.

A statement on the Bahrain News Agency late on Monday said Bahrain's Foreign Ministry had summoned charge d'affaires Mehdi Islami to inform him diplomat Hojjatullah Rahmani had 72 hours to leave "based on his link to the spy cell in Kuwait".

"Bahrain calls on Iran to desist from these serious violations of standards of international relations which are a threat to the security and stability of the region," it said.

This month Kuwait expelled three Iranian diplomats for involvement in an alleged spy ring, prompting Tehran to order three Kuwaiti diplomats to leave Iran.

That was after a Kuwaiti court sentenced two Iranians and a Kuwaiti to death in March for involvement in espionage.

Bahrain, a U.S. ally that hosts the U.S. Fifth Fleet, has also begun the trial of two Iranians and a Bahraini on charges of spying for Iran's Revolutionary Guards.

Iran complained to the United Nations over the recent Bahrain crackdown that has continued with the arrests of hundreds of activists and deaths of some in police custody.

Iran's Foreign Ministry spokesman Ramin Mehmanparast said Iran may take "retaliatory measures", Iranian media reported.

"The latest move by the Bahraini Foreign Ministry is against the two countries' good neighbourly relations and not based on realities," he was quoted as saying.

Reuters