Naveed Mehr, the main accused, was allegedly involved in firing on the Pakistan Tehreek-e-Insaf (PTI) founder in November 2022, while his accomplices Waqas and Tayyab had provided him arms.

A PTI worker died and 14 others, including Khan, were injured in the gun attack in the Wazirabad area, some 150 km from Lahore, where the party’s “Haqeeqi Azadi” (real freedom) march against the-then federal government led by Shehbaz Sharif had stopped on its way to Islamabad.

Khan, 71, had reportedly suffered three bullets to his leg. The gun-toting prime suspect Mehr was overpowered by the PTI workers from the crime scene.

"On Tuesday, the Anti-Terrorism Court (ATC) Gujranwala held the hearing of the Imran Khan attack case in which charges were framed against three suspects. The suspects who were present in the court pleaded not guilty," a court official told PTI after the hearing.

The official said according to the charges Mehr opened fire on the container where Khan had boarded along with other PTI leaders. Bullets hit Khan's leg. The other two suspects -- Waqas and Tayyab -- had provided Mehr with weapons. The court adjourned the hearing till May 25.

Khan had termed the attack a "planned assassination attempt" and named Inter-Services Intelligence (ISI)'s then Major-General Faisal Naseer behind it. He had also accused Naseer of killing Pakistani TV anchor Arshad Sharif in Kenya.

Khan had also named Prime Minister Shehbaz Sharif and then Interior Minister Rana Sanaullah as co-plotters in the assassination attempt.

"Two to three people were behind the plot to assassinate me. I know that the country’s armed forces are giving sacrifices for the country but there are black sheep in every institution," Khan had said. Khan has been imprisoned in high-security Adiala jail in Rawalpindi since August last year in several cases.

A Punjab police investigation into the case had claimed that shots were fired by “three unknown shooters" from a considerable height other than the gun attack carried out by the prime suspect, Mehr, from the ground.