Pakistan police warned Sunday they would come down hard on illegal gatherings after the party of jailed former prime minister Imran Khan urged supporters to protest against alleged rigging in last week's election.

Independent candidates — most linked to Khan's Pakistan Tehreek-e-Insaf (PTI) Party — took the most seats in the polls, scuppering the chances of the army-backed Pakistan Muslim League-Nawaz (PML-N) to win a ruling majority.

However, independents cannot form a government and the country faces weeks of political uncertainty as rival parties negotiate possible coalitions.