A court in Bahrain has handed down prison sentences to 139 people, including 69 life sentences, for terrorism offences after one of the biggest mass trials in the country’s history.

All but one also had their citizenship revoked, the public prosecutor, Ahmad al-Hammadi, said in a statement on Tuesday. Local news outlets said the defendants were accused of building a cell called “Bahraini Hezbollah”, similar to the Lebanese armed group funded by Iran, in order to sow discord in the Gulf kingdom.

Some had trained in Iran, Lebanon and Iraq, “at the behest of Iranian regime leaders who ordered the Iranian Revolutionary Guard elements to unify the Bahrain-based terrorist elements to carry out their plots and acts of terrorism against Bahrain,” Hammadi said.

Those tried were found guilty of training with and using illegal weapons and explosives, detonating bombs and attempted murder, and other sentences handed down ranged from between three and 10 years.

All the detainees are believed to be members of the Sunni-ruled country’s Shia majority, which has long accused the kingdom of discriminating against them. Thirty defendants were acquitted, Hammadi said. Fifty-eight of the defendants were tried in absentia, a judicial source told Agence France-Presse.

According to rights groups, Bahrain is increasingly using terrorism-related charges and the removal of citizenship to crack down on mostly peaceful political activists. Opposition members and rights activists have been jailed or fled, and authorities have denied multiple accusations of torture.

Since new laws were introduced in 2012 after the previous year’s Arab Spring protests, 990 people have had their Bahraini citizenship revoked, 180 of them in 2019 alone, and mass trials have become commonplace.

In February, 167 people who were arrested in 2017 at a sit-in outside the home of Bahrain’s leading Shia cleric were sentenced to between six months and 10 years in prison. Last May, 115 people were stripped of their citizenship after a single trial. Their sentences were upheld in January.

Last September, 169 people were also charged with being members of Bahraini Hezbollah.

Sayed Ahmed Alwadaei, an advocacy director at the London-based Bahrain Institute for Rights and Democracy, said the ruling on Tuesday was the biggest single case of citizenship stripping since 2012.

“Today’s trial is a dark stain on Bahrain’s history and marks a tragic moment in the ongoing crackdown on civil liberties in Bahrain,” he told the Guardian. “Most … of the men convicted seem to have had their citizenship revoked, rendering them stateless, and all appear to be from Bahrain’s Shia community. The unabated revocation of citizenship sets a very dangerous precedent for the future of Bahraini society.”

Amnesty International condemned the court’s decision, calling it a “mockery of justice”. Lynn Maalouf, the organisation’s Middle East research director, said: “Arbitrarily stripping people of their citizenship and rendering citizens stateless are blatant violations of international law. Bahrain’s authorities must immediately stop relying on these unlawful measures as punishment.”

It was not immediately clear whether the detainees stripped of Bahraini citizenship would be deported or where they could go. In 2018, eight Bahrainis whose citizenship had been revoked for “damaging state security” were sent to Iraq.

Since the 2011 pro-democracy uprising, there have been sporadic outbreaks of violence including bomb attacks in Bahrain, a western-allied island state that is home to the US navy’s fifth fleet. The country accuses Iran of stoking Shia militancy inside its borders by providing training and weapons to various armed groups.

Tehran supported the Arab Spring protests in the country but has repeatedly denied backing local militant groups that have carried out attacks on security forces.