Opposition leader Imran Khan threatens to shut down Pakistan with protests

Pakistani cricketer-turned-opposition leader Imran Khan has vowed to continue his more than three-month campaign to oust Prime Minister Nawaz Sharif by shutting down cities nationwide on December 16.

"They left us with no option, and now we are going to make it difficult for Sharif to run the government," Khan told thousands of supporters in Islamabad late on Sunday. "If the government doesn't respond positively, then I have another plan."

Khan, who alleges massive rigging in last year's election that swept Sharif to power for the third time, has been holding demonstrations around the country since mid-August.

But his campaign has lost momentum after so far failing in its aims. "We will close the whole of Pakistan on December 16," he told tens of thousands of supporters near parliament on Sunday evening, adding that his party workers would paralyse major cities starting with Lahore, Sharif's seat of power.

Khan also called for a speedy judicial probe into allegations of systemic ballot-stuffing in the 2013 poll, which saw Pakistan's first democratic handover of power and was rated by local and foreign observers as "credible".

"The ball is in your court, Nawaz Sharif - do your talks, do your investigations and solve the issue," said the former cricket star. Followers of Khan and firebrand cleric Tahir-ul-Qadri clashed with police in late August after they tried to storm the prime minister's residence, leaving three demonstrators dead and hundreds injured on both sides.