The Gulf state of Bahrain Tuesday jailed 138 people and revoked their citizenship for plotting to form a “terror” group with links to Iran's Revolutionary Guards, the public prosecutor said.

The verdict was swiftly condemned by the Bahraini opposition, while human rights group Amnesty International decried the “mockery of justice” and “mass arbitrary denaturalisation”.

The court, whose rulings can be appealed, handed the men prison terms of three years to life for having tried to build a Bahrain Hezbollah, similar to the Shiite militia active in Lebanon, said prosecutor Ahmad al-Hammadi.

Some members had received military training in Lebanon, Iran and Iraq, he said in a statement.

Another man was also jailed but his citizenship was not revoked, while 30 others were acquitted, said the statement posted on the prosecution Instagram account.

A judicial source said all the convicts are members of the Shiite community in the Sunni-ruled Gulf state. The source also said that 111 were already in custody while 58 were sentenced in absentia.

Amnesty International described the sentences as “outrageous” and a sign of Bahrain's authorities' disregard for international judicial standards.

The trial “demonstrates how Bahrain's authorities are increasingly relying on revocation of nationality as a tool for repression,” said Lynn Maalouf, Middle East research director at Amnesty.

Bouts of unrest

Ruled for more than two centuries by the Sunni Al-Khalifa dynasty, Bahrain has a majority Shiite Muslim population, according to unofficial estimates contested by the government.

The small Gulf state, a key US ally located between rivals Saudi Arabia and Iran, has been gripped by bouts of unrest since 2011, when authorities cracked down on Shiite-led protests demanding political reform.

Since then, hundreds of protesters have been jailed or stripped of their nationality, with Bahrain claiming Iran trained and backed demonstrators in order to topple the Manama government — an accusation Tehran denies. All opposition groups have been banned and disbanded.

The king last year signed off on a decree granting military courts the right to try civilians accused of “terrorism”.

In June, Bahrain amended its law on political rights, prohibiting leaders and members of dissolved political associations from running in legislative elections.

'Terrorism' trials

In Tuesday's court ruling, the prosecutor said 69 defendants were sentenced to life in jail, 39 to 10 years, 23 to seven years and the rest to between three and five years imprisonment.

Ninety-six of the defendants were also fined 100,000 Bahraini dinars ($265,000) each.

The opposition Bahrain Institute for Rights and Democracy (BIRD) said the mass sentencing was “the largest single incident” since the Bahraini government began revoking nationalities of opponents in 2012.

Since then, Manama had stripped the nationalities of 990 people, including 180 this year, the institute said.

“BIRD condemns the outcome of this deeply unfair trial in the strongest possible terms and urges the authorities to quash the sentences and restore the citizenships,” the group said in a statement.

“This is not the first incident where the Bahrain judiciary has held a mass trial to convict individuals on terrorism-related offences,” it said.

In May 2018, 115 individuals were sentenced to prison and their citizenships were revoked, it said.

In other recent high-profile trials, Bahrain's prominent rights defender Nabeel Rajab in December lost his final appeal against a five-year jail term for writing tweets deemed offensive to the state.

In January, Bahrain's supreme court upheld a life term against Sheikh Ali Salman, the head of the main Shiite opposition group Al-Wefaq, for allegedly spying for rival Qatar.