Clashes erupted on August 15 as thousands of antigovernment protesters headed toward the Pakistani capital to demand that Prime Minister Nawaz Sharif step down.
The clashes broke out in the eastern city of Gujranwala, where cricketer-turned-politician Imran Khan was leading one of the convoys on its way to Islamabad.
Officials from Khan's Tehrik-i-Insaaf party said shots were fired at their convoy, a claim the police denied.
A second antigovernment convoy also heading to Islamabad was led by cleric Tahir ul-Qadri.
Both convoys set off on August 14 from the eastern city of Lahore.
The protesters denounce government corruption and allege the 2013 elections that brought Sharif to power were rigged.
They are expected to march later on August 15 into Islamabad, where thousands of additional troops have been deployed ahead of their arrival.
Based on reporting by AFP, AP, and dpa
