Islamabad: Ending a two-day blockade of Nato supplies to Afghanistan through the historic Khyber Pass by thousands of his supporters, politician Imran Khan on Sunday vowed to force a permanent closure if the US drone attacks in the tribal areas are not stopped.

Khan, chief of his Tehreek e Insaaf (Justice Movement) party, led a mass sit-in in the suburbs of the northwestern provincial capital, Peshawar, bringing to a standstill hundreds of trucks and oil tankers that daily carry fuel and other supplies for Nato troops battling Taliban insurgents in Afghanistan.

He said if US drone raids were not halted within a month his party would stage such sit-in protests at various points on the route from Karachi harbour to the northwestern province in order to choke flow of Nato supplies.

"We will also, in the next phase, march onto Islamabad if the government fails to halt drone strikes in which innocent men, women and children are being killed," the former cricketer-turned-politican said, urging all political parties to join the campaign.

He demanded that human rights activists and domestic and international media be allowed entry into the tribal areas to ascertain whether those killed and injure in drone attakcs were militants or innocent civilians.

Javed Hashmi, a senior figure in the main opposition Pakistan Muslim League-N (PML-N) of former prime minister Nawaz Sharif, and Marvi Memon, a female federal lawmaker belonging to PML-Q, joined the Tehreek-e-Insaaf protest on the second day.

Khan lashed out at the Pakistan People's Party government and its leadership, accusing them of corruption, misrule and turning thec ountry into a US client state. He called upon the youth to rise up and support his party to make Paksitan a truly free country

"US is responsible for all bloodshed in the region; it must leave so that peace is restored," he told the flag waving people, who frequently shouted anti-US slogans.

In comments to the media, PPP government's itnerior minister Rehman Malik said the sit-in was an anti-Pakistan act.

Malik said drone strikes in the tribal territory had started during the regime of former military ruler Pervez Musharraf and asked Imran Khan as to why he did not agitate then against these raids.