The mass sentencing was "the largest single incident" since the government began stripping opponents of their citizenship rights in 2012, a rights group said.
A court in Bahrain sentenced 139 people to jail on terrorism charges on Tuesday and revoked the citizenship of all but one of them, the public prosecutor said, in the latest mass trial in the Gulf Arab state.
Bahrain, which hosts the US Navy's Fifth Fleet, has prosecuted hundreds of protesters in mass trials and banned main opposition groups. Most of the leading opposition figures and rights activists are imprisoned or have fled abroad.
Such trials, condemned by rights groups, became commonplace after a failed uprising in 2011 led by members of the Shia Muslim majority in the Sunni-ruled country was crushed with the help of neighbour Saudi Arabia.
Bahrain revoked the 138 people's citizenship for plotting to form a "terror" group with links to Iran's Revolutionary Guard, Ahmad al Hammadi said in a statement.
The High Criminal Court handed out jail terms, including life in prison to 69 of the defendants, for having tried to build a Bahrain Hezbollah, similar to the Shia militia active in Lebanon. Some members had received military training in Lebanon, Iran and Iraq, according to the statement.
The crimes included joining a "terrorist" group, bombings, attempted murder and receiving arms and explosives training.
The defendants have the right to appeal the ruling, the statement said.
Of those sentenced, 60 were in absentia, a defence lawyer said.
Since the uprising eight years ago, the Gulf island nation has seen periodic clashes between protesters and security forces, which have been targeted by several bomb attacks.
The Britain-based Bahrain Institute for Rights and Democracy criticised the trial as "deeply unfair" and said Bahrain was using revocations of citizenship as a "tool of oppression."
The Institute added that the mass sentencing was "the largest single incident" since the Bahraini government began revoking nationalities of opponents in 2012.
Tuesday's decision took the number of citizenship revocations in Bahrain to 990, 180 of them this year, the institute said in a statement.
"A mass trial cannot produce a just result and rendering people stateless in a mass trial is a clear violation of international law," institute Director of Advocacy Sayed Ahmed Alwadaei said.
The government denies deliberately targeting the Shia political opposition, saying it is only acting to preserve Bahrain's national security.