CAIRO -- In the latest sign of a crackdown on dissidents in Bahrain, the government on Wednesday revoked the citizenship of 31 people, including exiled political activists and former opposition members of Parliament, citing security concerns.
The decision was announced by the state news agency, which offered no details about individual cases, saying only that the law permitted the government to re-evaluate citizenship when the holder "causes damage to state security." Those affected by the decision have the right to appeal, the agency said.
Opposition activists said the people on the list -- all but one of them men -- were members of Bahrain's Shiite majority, which has led a 21-month uprising against the Sunni monarchy to win greater political freedoms and to dismantle what Shiites complain is a system of entrenched, official discrimination.
The rare move by the government came after weeks of escalating tensions in the island nation, which is home to the United States Fifth Fleet. In recent days, the government has banned demonstrations and arrested a prominent human rights advocate. On Monday, two foreign workers were killed in a spate of bombings in the capital, Manama.
The government hinted that the Lebanese Shiite group Hezbollah had played a role in the bombings, without providing evidence. Officials said four suspects had been arrested.
The list released Wednesday included two brothers who had served in the Bahraini Parliament, and a university professor based in Sweden. Matar Matar, a member of the largest opposition group, Wefaq, who was not on the list, said it included dissidents who had been charged with political crimes but others who had never faced charges, or were not deeply involved in politics.
Some of the people had called for the overthrow of the monarchy, and others were members of the opposition who had favored negotiations with the government about reforms. In a statement, Amnesty International said the "arbitrary deprivation of nationality" and the fact that inclusion on the list made stateless those people who did not hold dual citizenship were "frightening and chilling," and a violation of international law.
Jawad Fairooz, a former Parliament member from Wefaq, learned of the decision while in London from his wife, who had heard it on the news. Mr. Fairooz, who faces charges related to his role in the uprising, also learned he had been sentenced to 13 months in prison, on charges including illegal gathering.
His brother, Jalal Fairooz, who also served in Parliament and is on the list, has never been charged with a crime, Jawad Fairooz said. "There's no logic to it," he said.
Another dissident on the list, Saeed al-Shehabi, a journalist who has lived in London since the 1970s, said the government was "reacting to my lifelong struggle against dictatorship.
"I'm surprised that they would go this far," he said, adding that a lack of pressure on the Bahraini government by its allies, including the United States, "makes it feel it can do this with impunity."
Correction: November 8, 2012, Thursday
This article has been revised to reflect the following correction: An earlier version of this article, and the headline, referred incorrectly to the Bahrainis whose citizenship was revoked. Thirty are men and one is a woman. They are not all men.
This article originally appeared in The New York Times.