Faisalabad: The Pakistan Tehreek-i-Insaf (PTI) has called for a day of mourning Tuesday in protest against the killing of a party worker during its clashes with the Pakistan Muslim League-Nawaz (PML-N) supporters in Faisalabad.

PTI chief Imran Khan vowed that the death of Haq Nawaz, "would not go to waste" while he strongly condemned the PML-N government of Prime Minister Nawaz Sharif, the Dawn reported.

Following the deadly clashes in Faisalabad Monday, the PTI also called off talks with the government.

Imran had earlier promised that the strike in Faisalabad would be the first of a series to target major cities in the country after leading a demonstration in Islamabad that had shut down the city and sparked clashes.

The party has been demanding Prime Minister Sharif's resignation alleging rigging in the May 2013 general election that brought Sharif to power.

Monday's violence has complicated an already tense political situation with both sides blaming the other for the current impasse.

Imran had urged traders to keep their businesses shut in Faisalabad Dec 8, requesting citizens to sacrifice "one day to liberate themselves".

However, after the killing of the party activist in Faisalabad ahead of his call for a shutdown of the city, the cricketer-turned-politician vowed that a "storm" would be unleashed to "free the country from its oppressive rulers".