Bahrain Mirror - AFP: Kuwait on Thursday expelled Iranian diplomats and closed some embassy missions after the emirate's top court convicted a "terror" cell of links to Iran, the foreign ministry said.

The action was taken after a supreme court ruling last month said "Iranian sides helped and supported the cell members," the ministry said in a statement.

A senior government official, speaking on condition of anonymity, told AFP around 15 diplomats were ordered to leave.

Kuwait also ordered the closure of the Iranian "military, cultural and trade" missions, the official said.

It was not immediately known if the Iranian ambassador is among the diplomats ordered to leave.

Last month Kuwait's supreme court sentenced the mastermind of the cell to life in jail and condemned 20 others to various prison terms for alleged links with Iran and Lebanese militia Hezbollah, and plotting terror attacks in Kuwait.

State Minister for Cabinet Affairs Sheikh Mohammad Abdullah Al Sabah, who is also acting information minister, confirmed Kuwait had taken diplomatic action against Iran.

"Following the supreme court ruling on the case... the government of Kuwait has decided to take measures, in accordance with diplomatic norms and the Vienna Convention, towards its relations with Iran," Sheikh Mohammad told AFP.

The row comes at a time when Kuwait is trying to mediate an end to the Gulf's worst diplomatic crisis in years, after Saudi Arabia and its allies cut ties with Qatar over accusations it is too close to Iran and funds extremists.

The Kuwaiti newspaper Al Seyassah reported on Monday that 14 of the cell's 26 members had fled to Iran by sea.

They were convicted by a lower court early last year but acquitted on appeals several months later and set free.

The supreme court, whose rulings are final, overturned their acquittal on June 18 and sentenced them to between five and 15 years in prison.

Kuwait's interior ministry confirmed on Tuesday that the 14 men were on the run but it said that they had not left the country through official exit points.

The cell was busted in August 2015 and large quantities of arms, ammunition and explosives were seized from them, according to the Kuwaiti authorities.

Kuwaiti courts convicted them of working for Iran's Revolutionary Guards and Hezbollah. They were also convicted of smuggling explosives from Iran.

The only Iranian member of the cell was sentenced to death in absentia by the lower court early last year.

In February, Iranian President Hassan Rouhani visited Kuwait City a month after the emirate launched a dialogue with Iran in a bid to normalise Gulf-Iran relations.

In March 2011, a Kuwaiti court condemned four people of forming a spy cell for Iran. That led to the expulsion of ambassadors by the two countries but they returned a few months later.