The jailed leaders of a radical opposition group on Tuesday urged Prime Minister Nikol Pashinian to ensure the quick release of their supporters who stormed a police station in 2016, warning that their continued imprisonment could have “severe consequences” for Armenia.

In an open letter, Zhirayr Sefilian and Varuzhan Avetisian criticized Pashinian for his reluctance to pressurize courts and law-enforcement bodies into freeing these and other “political prisoners.”

“So far one has been left with the impression that you have washed your hands and are urging the political prisoners and other citizens to count on a miraculous spiritual and moral transformation of criminal prosecutors and judges,” they said.

Sefilian is the top leader of the Founding Parliament movement who was arrested in June 2016 and subsequently sentenced to 10.5 years in prison for plotting an armed revolt against the government, a charge he strongly denies.

Sefilian’s arrest came less than a month before three dozen Founding Parliament members led by Avetisian seized a police base in Yerevan to demand his release and then President Serzh Sarkisian’s resignation. The armed group calling itself Sasna Tsrer laid down its weapons after a two-week standoff with security forces, which left three police officers dead. Its members are currently standing three separate trials.

Pashinian pledged to seek the release of all “political prisoners” immediately after he swept to power in a democratic revolution earlier this month. But he made clear that he will use solely legal mechanisms for that purpose.

Pashinian has publicly listed Sefilian but not Avetisian and other jailed gunmen among the individuals who he believes were jailed for political reasons. He said last week that the Sasna Tsrer case is “a bit different” because of the three police casualties. He said it will be resolved as a result of public “discussions” that must involve relatives of the three slain policemen.

Avetisian condemned Pashinian’s remarks as “buffoonery” and “false humanism” on May 16. He again strongly defended the 2016 attack, saying that casualties are inevitable during such “rebellions.”

“If the political prisoners, including the Sasna Tsrer members, remain in jail, that will be fraught with severe consequences for our country and the revolution,” Avetisian and Sefilian warned in their letter to Pashinian.

“Of course, it is good that you reject in principle ‘telephone’ justice,” they said. “But the supremacy of law has a value and meaning only if it serves the supremacy of rights. Therefore, while rejecting that illegal option of direct control, you can and must use all available legitimate levers of indirect leadership to change the atmosphere in the prosecutor’s office and courts … and guarantee fair decisions by them.”

The 2016 attack on the Yerevan police base was condemned by the United States and the European Union. “We abhor the actions of Sasna Tsrer and others who use violence or who threaten to harm others to serve their political agenda,” Richard Mills, the U.S. ambassador to Armenia, said as recently as in March.