Thousands of supporters of two opposition leaders, demanding resignation of Pakistani Prime Minister, Nawaz Sharif, late Tuesday entered a high security zone in the capital city Islamabad, raising concerns about a possible showdown with the security forces.
The leaders Imran Khan and Tahir ul Qadri had earlier not to enter the Red Zone that houses the diplomatic missions, the Prime Minister and Parliament Houses and several other key buildings.
Imran Khan alleges the last year's parliamentary polls were " rigged" to pave the way for the election of Prime Minister Nawaz Sharif.
The protesters removed containers from the routes and ignored all warnings by the police. At least one policeman was injured when the protesters used batons to beat him when a group of policemen tried to stop the demonstrators from moving forward.
The police did not intervene despite promises by the opposition leaders that they would not cross into the sensitive areas in the capital.
Prime Minister Nawaz Sharif has asked the security forces not to use force in view of the participation of women and children in the protests, Information Minister Pervez Rashid said.
The minister accused Khan and Qadri of conspiring against the democratic system.
The government deployed hundreds of army troops for the security of the sensitive areas, besides thousands of paramilitary troops and policemen.
The opposition activists started moving towards the parliament building after staging a sit-in for six days in Islamabad to press for resignation of the Prime Minister.
They had started the march from the eastern city of Lahore on August 14, the day when the nation was celebrating the country's Independence Day.
Prime Minister Nawaz Sharif has rejected calls for his resignations but accepted demand for probe into the polls rigging, however, Khan rejected the investigation.
The two opposition leaders have also rejected dialogue offer.
Imran Khan has also launched a Disobedience Movement, asking the people not to pay taxes and utility bills. The business community and the people have rejected Khan's appeal.