A Pakistani opposition leader was among more than three dozen members and supporters of former prime minister Imran Khan's party sentenced to 10 years in prison on Tuesday, the government said.

The sentences were handed down by anti-terrorism courts in the eastern cities of Lahore and Sargodha after dozens were found guilty of involvement in anti-government riots when Khan was first arrested.

"Punjab Assembly's Opposition Leader Malik Ahmad Bhachar has been awarded a 10-year sentence," deputy minister of law Aqeel Malik said in a press conference.

Bhachar helms the opposition in Punjab, Pakistan's most populous and politically influential province. Following Tuesday's verdict, he pledged on social media "not to abandon" support for Khan.

A spokesman for Khan's Pakistan Tehreek-e-Insaf (PTI) party said that Bhachar was not arrested until Tuesday evening.

In addition to Bhachar, a court in Sargodha also sentenced a sitting lawmaker, a former parliamentarian and 32 other supporters of PTI to 10 years each for attacking government buildings, Malik said.

Separately, a court in Lahore sentenced eight PTI members to 10 years in prison each for their involvement in riots in that city.

Those sentenced include former governor of Punjab province Omar Sarfraz Cheema, former provincial minister Yasmin Rashid, and Ejaz Ahmed Chaudhary, a sitting senator.

However, former foreign minister Shah Mahmood Qureshi was acquitted along with five others.

Khan, in office from 2018 to 2022, was initially arrested in May 2023, sparking nationwide unrest, some of which targeted military facilities.

Tuesday's sentences were handed down for attacks on police and civilian installations in Khan's home constituencies of Mianwali city and Lahore. Those accused of targeting military installations are facing separate trials in military courts.

PTI has vowed to challenge the verdicts in higher courts. (AFP)