The Bahraini government, facing protracted unrest by its Shi'ite Muslim majority, has revoked the nationality of 31 men for damaging national security, the state news agency BNA reported on Wednesday.
The men include London-based dissidents Saeed al-Shehabi and Ali Mushaima, the son of jailed opposition leader Hassan Mushaima, as well as clerics, human rights lawyers and activists, according to Mohammed al-Mascati, head of the Bahrain Youth Centre for Human Rights.
In April, Ali Mushaima scaled the roof of Bahrain's embassy in London to publicise opposition demands for democratic change.
Also on the list published by BNA were two former parliamentarians from the leading Shi'ite party Wefaq, Jawad and Jalal Fairooz, who are of Shi'ite Iranian descent.
The ruling Al Khalifa family used martial law and help from Gulf neighbours to put down a Shi'ite-led uprising against alleged discrimination in March last year, but unrest has resumed. Shi'ite protesters and police clash almost daily.
Bahrain, where the U.S. Fifth Fleet is based as a bulwark against Iran, accuses Tehran of encouraging the unrest and has promised a tough response as talks with the opposition have stalled. Iran has denied meddling in Bahrain's affairs.
Matar, a senior member of Wefaq, said the decision to revoke nationality was an escalation of the conflict in Bahrain and accused the government of having granted citizenship to Sunni foreigners to boost their numbers in the country.
"They want to replace us as a pro-democracy movement via nationalisation of mercenaries and revoking our nationality," Matar said.
"This is a reflection of a complex persecution policy against race, sect and political orientation. It is against Bahrain's Persian minority, Shi'ites and the pro-democracy movement in general."
Amnesty International said it appeared as though Bahrain had withdrawn the men's citizenship on the basis of their political views.
"Most worryingly, the authorities are making some in the group stateless. This, as well as any arbitrary deprivation of nationality, is prohibited under international law," said Philip Luther, Amnesty's director for the Middle East and North Africa.
"We urgently call on the Bahraini authorities to rescind this frightening and chilling decision."
It was not clear whether the men stripped of their nationality would be expelled from Bahrain.
In a similar move last December, the United Arab Emirates revoked the citizenship of seven Islamist activists, saying they posed a threat to national security. Some of the men had demanded greater powers for the Federal National Council, an elected body which advises the government.
The Bahraini government said on Tuesday it had arrested four suspects in multiple bombings that killed two people in the capital Manama, and it accused the Lebanese militant group Hezbollah of being behind the attacks.
The five home-made bombs on Monday bore the hallmarks of Hezbollah, the Shi'ite group allied with Iran, authorities said. Hezbollah has previously denied interfering in Bahrain.