Muhammad Tahir-ul-Qadri, who left Canada in June to return to Pakistan, is calling on thousands of his supporters to march on the capital Islamabad on Thursday in a bid to oust the government of Prime Minister Nawaz Sharif.
Qadri and another anti-government leader — former cricket legend Imran Khan — allege that the nationwide election last year was widely rigged and are demanding a new vote.
On Sunday, police in the city of Lahore opened a murder investigation against Qadri after a police officer died during clashes with his supporters.
Police allege the cleric incited people to violence, but Qadri tells The Canadian Press in a telephone interview the allegations are "fabricated."
The Department of Foreign Affairs said it was aware of media reports about the murder investigation against Qadri and it was monitoring the situation, but refused to comment further, citing privacy reasons.