"We have registered a case against him in Bani Gala police station for interfering in police work and forcibly releasing the prisoners," police spokesman Naeem Ahmed said.

The former cricketing star was coming out of his house on Sunday when he saw about 15 of his supporters were being shifted to a nearby police station. On seeing Khan, the workers cried for help.

Khan then stopped police vehicles and forced them to release his supporters.

The spokesman said that Khan's supporters were arrested for violating section 144 which was imposed in the capital.

Already several criminal cases have been registered against Khan since his arrival here with thousands of his party workers to force Prime Minister Nawaz Sharif to quit.

Khan has not been arrested in any case so far but police plan to move against him once the protests are over.

Khan wants Sharif's ouster over alleged rigging in last year's poll which his party lost. He is agitating since August 14. At least three people have been killed and over 550 injured during the protests.

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