Former Pakistani prime minister Imran Khan issued a stern warning to Pakistan's leadership early on Thursday morning, stating that he would lead a three million-person march on the capital if new elections were not scheduled within the next six days.

Khan spoke at a demonstration in Islamabad attended by tens of thousands of protesters attempting to overthrow the government and force early elections. Important structures, including the Parliament and the offices of the president and prime minister, Shahbaz Sharif, had been guarded by troops earlier. The measures were taken when demonstrators and police clashed.

Khan stated in his speech that five of his followers had been killed in the rioting around the nation. The administration did not immediately react to Khan's assertion, whose followers were dispersing. Khan has previously pledged to engage in a protracted sit-in until his demands were met.

Khan, a former cricket star turned Islamist politician, served as prime minister for more than three and a half years until he was removed from office by a vote of no confidence in Parliament last month. Since then, he has led protests throughout the nation, claiming that his departure from the government resulted from a US-organized plot and Sharif's involvement. Both parties have disputed the charge.

Khan began his march on Islamabad in Peshawar, Pakistan's northwest. Initially, clashes broke out in the eastern city of Lahore as riot police shot tear gas and pushed back hundreds of stone-throwing protesters attempting to clear a barrier near the town to board buses going to Islamabad.

Dozens of Khan's supporters also briefly battled with police in Islamabad, where demonstrators torched bushes along a central avenue, sending smoke and flames into the air. Disputes were also reported in other cities, including Karachi, where protesters burned a police vehicle.

At least a dozen protesters and multiple police officers were injured. Major routes leading into Islamabad were blocked with dozens of shipping containers and trucks before Wednesday's demonstrations.

Khan took a chopper to a route approximately 100 kilometers (62 miles) northwest of Islamabad, where he denounced the police crackdown and urged supporters to attend the march.

Wednesday, the authorities responded by initiating a crackdown and arresting over 1,700 Khan supporters. The measures were announced after a police officer was slain during a Tuesday raid on the Lahore residence of a prominent Khan supporter.

Separately, discussions between Islamabad and the International Monetary Fund finished in Qatar on Wednesday without Pakistan getting a $6 billion bailout package from the international lender.

After the talks, the IMF pushed Pakistan to eliminate gasoline and energy subsidies. The administration of Khan approved the grants in February, prompting the IMF to withhold a $1 billion payment at the time.