Bahraini security forces are searching for three suspects believed to be planning terror attacks in the kingdom and harbouring materials used to make explosives, media reports said on Thursday.
They have "identified three suspects believed to be involved in these terror activities ... for whom there is a search operation underway," public security chief Tareq Hasan told reporters in Manama late on Wednesday, according to the state news agency BNA.
Hasan said recent raids uncovered "terrorist hideouts ... which resulted in the seizure of materials and tools used in the manufacture of explosive devices."
He said the suspects involved managed to flee after the hideouts were raided.
The United States, whose support for the government has rattled rights advocates, praised the regime for its "thorough and professional investigation" and voiced concern over the reported discovery of explosives.
"There is no justification for any party to hold such material, the use of which would exact an enormous human toll and severely escalate tensions in the country," State Department spokeswoman Victoria Nuland said in Washington.
Last week, police announced they had arrested five of a group of 20 people wanted over "terror attacks," which included bombings and harming civilians and security personnel.
On May 5, the interior ministry said four policemen were wounded in a "terror blast" in a Shiite village.
A similar explosion in another Shiite-populated village left four policemen wounded in April.
Meanwhile, a court lifted a travel ban on prominent Shiite rights activist Nabil Rajab, a day after he was released from prison, a court official told AFP on Thursday.
The official said Rajab was also ordered to pay an $800 (645 euro) fine for posting on his Twitter account comments deemed insulting to the security forces.
Rajab was released Wednesday after a three week detention for his tweets.
He remains on trial for five separate charges, including two related to comments on the microblogging site and three for anti-regime protest actions.
The tiny Gulf kingdom's Shiite majority claim marginalisation by the Sunni regime, and have for months been calling for political and social reforms.
Amnesty International says around 60 people have been killed since the anti-regime protests first erupted in February 2011.