Bahrain announced on Tuesday the arrest of nine Shiites it said are linked to Iran and that were planning to attack a prison to facilitate a jail break.
The interior ministry said arms, ammunition and a plan for attacking the prison were seized.
Those arrested belong to a group called Jaish al-Imam (Army of the Imam), who were planning to carry out attacks on key installations in the country, the ministry said.
This "terrorist cell," which the ministry said had links to Iran, Iraq and Lebanon, was busted in February. Eight of its members were said to have received weapons and explosives training and were financed from abroad.
Bahrain is a country with a Shiite Muslim majority population that is ruled by a Sunni Muslim dynasty.
Relations between Bahrain and overwhelmingly Shiite Iran have been tense since the authorities in Manama, with the help of Saudi Arabia and other Gulf neighbours, suppressed a pro-democracy movement largely led by Shiites.
At least 80 people have been killed in Bahrain since then, but despite the heavy-handed demonstrations continue.