Thousands of protesters set off from the Pakistani city of Lahore on Thursday to march on the capital in a bid to unseat the government, which they claim was elected by fraud.

Thousands of protesters set off from the Pakistani city of Lahore on Thursday to march on the capital in a bid to unseat the government, which they claim was elected by fraud.

Supporters of cricketer-turned-politician Imran Khan and populist preacher Tahir-ul-Qadri massed separately in Lahore before beginning the 300-kilometre (190-mile) journey to rally in Islamabad.

Both Khan and Qadri say the May 2013 general election was rigged and want Prime Minister Nawaz Sharif to resign and hold new polls. Sharif won by a landslide.

The two groups, travelling in motorized convoy to Islamabad on the anniversary of Pakistan's independence from Britain, made slow progress leaving Lahore.

The authorities had insisted Qadri's Pakistan Awami Tehreek (PAT) march would not be allowed, but relented in the afternoon.

Khan, whose Pakistan Tehreek-e-Insaaf (PTI) political party came third in the polls, was earlier given the go-ahead for his "Azadi" (freedom) march.

Government officials have accused the march organizers of trying to derail democracy and Sharif said the marches were a distraction from more pressing issues.

Pakistan is currently waging a military offensive against Taliban hideouts in its northwest, while also trying to boost a sagging economy and solve a chronic power supply crisis.

"This is the real Azadi march, taking place here, both civil and military leadership is together here and celebrating Pakistan's independence day, what can be a bigger march than this?" said Sharif.

The prime minister spoke at a ceremony to reopen a house once owned by Pakistan's founding father Muhammad Ali Jinnah, alongside army chief General Raheel Sharif, in an apparent show of unity.