ISLAMABAD - Thousands of protesters led by Pakistan's opposition leader Imran Khan on Saturday arrived in the capital Islamabad to try to topple the government he alleges was elected by fraud.
Cricketer-turned-politician Khan says the May 2013 general election that brought Prime Minister Nawaz Sharif to power in a landslide was rigged, and has demanded he resign and hold new polls.
A populist cleric Tahir-ul-Qadri also led thousands of his followers alongside Khan in his own march on the capital to force the Sharif government to step down.
Both Khan and Qadri plan to rally in Islamabad until their demands for Sharif's resignation and for electoral reforms are met.
The demonstration in Islamabad is the culmination of the "long march" - in reality a motorised cavalcade - which set off Thursday from the eastern city of Lahore, around 300 kilometres (190 miles) away.
The marchers took more than 36 hours to reach the capital as convoys made stopovers in various cities along the road where they were warmly welcomed.
Police and witnesses said earlier on Friday that activists from Khan's Pakistan Tehreek-e-Insaaf (PTI) party clashed with supporters of Sharif's Pakistan Muslim League-N (PML-N) in the town of Gujranwala, some 200 kilometres (120 miles) southeast of Islamabad.
Khan said shots were fired on his march, telling ARY television news: "They threw stones at us...They fired bullets at us." However, police said there were no shots and an AFP photographer at the scene also heard no gunfire.
"Workers of PTI and PML-N clashed in Gujranwala and threw stones at each other," a police spokeswoman told AFP. "There was no firing incident," she added.
The AFP photographer said a group of up to 40 youths who were following the convoy and shouting slogans clashed with workers from Khan's party before being dispersed by police.
Marvi Memon, a PMLN member of parliament and spokeswoman, told AFP the events in Gujranwala were "regrettable" but said there was no shooting and her party's workers had been provoked by what she called Khan and Qadri's "violent speeches".
Punjab Chief Minister Shahbaz Sharif, the premier's brother, ordered an investigation into the clashes and appealed for calm.
Supporters of PTI, which came third in last year's election, lined up to welcome the convoy in towns along the Grand Trunk Road which links Lahore and Islamabad.
Exact numbers for the march have not been confirmed, organisers expect to get a clearer figure once participants assemble all together in Islamabad.
But Khan has already hailed it a success and put crowd figures at a million.
"I can only see that the 'monarchy' is nearing its end," Khan said, referring to Sharif.
"The people have decided. I said one million people will come to Islamabad, and they have come out."