Pakistan opposition leader Imran Khan and cleric Tahirul Qadri tonight marched with thousands of their supporters to enter the heavily fortified 'Red Zone', the capital's diplomatic and political enclave, as minor clashes took place between anti-government protesters and security personnel.

"Promise me, if something were to happen to me, you will take revenge from Nawaz Sharif," Khan said while addressing his supporters before starting his march towards the Red Zone that houses important government buildings including the Parliament House, Prime Minister House, President House, the Supreme Court besides embassies of various countries.

Unfazed by army deployment, the Pakistan Tehreek-i-Insaf chief and Qadri marched towards the Parliament demanding Prime Minister Nawaz Sharif's resignation, putting the PML-N-led government on the backfoot.

The police baton-charged Qadri's Pakistan Awami Tehreek protesters as they neared the parliament.