Pakistan military courts have convicted and sentenced 25 people for involvement in pro-Imran Khan unrest last year, the armed forces said Saturday, with the majority handed decade-long prison terms.

Ex-prime minister Khan was arrested in May last year after being ousted from office and mounting an unprecedented campaign of defiance against the nation’s powerful military leaders. His detention over graft allegations sparked nationwide unrest, some targeting armed forces installations, and prompting rare prosecutions of civilians in military courts.

Amnesty International called the move “an intimidation tactic, designed to crack down on dissent” and said it was “contrary to international law”. Military courts are largely opaque, but after months of confidentiality the military public relations wing named 25 people who have been prosecuted.

All of the convicted are men and 14 have been sentenced to a decade of “rigorous imprisonment”, the military said with the remaining 11 set to serve lesser prison terms. “All sentences announced by the military courts are disproportionate and excessive,” said a spokesman for Khan’s Pakistan Tehreek-e-Insaf (PTI) party. “These sentences are rejected.”

The verdicts were announced just three weeks after the capital Islamabad was gripped by fresh unrest, as tens of thousands of Khan supporters flooded in to demand his release. The government said at least five security personnel were killed whilst PTI allege at least 10 of their own were shot dead by security forces before crowds retreated.

A United Nations panel of experts found in September that Khan’s detention “had no legal basis and appears to have been intended to disqualify him from running for political office”.