Imran Khan addresses his supporters during the fourth day of Freedom March in Islamabad
Imran Khan (C), cricketer-turned-opposition politician and chairman of the Pakistan Tehreek-e-Insaf (PTI) political party, waves his hand while addressing his supporters during the fourth day of the Freedom March in Islamabad August 17, 2014. Tens of thousands of anti-government protesters flooded the centre of Pakistan's capital on Saturday, vowing to stay in the streets until Prime Minister Nawaz Sharif resigns. REUTERS/Faisal Mahmood (PAKISTAN - Tags: POLITICS CIVIL UNREST)
Tens of thousands rally in Pakistani capital, demanding PM quit
PAKISTAN-PROTESTS/ (PIX, TV,UPDATE 1):UPDATE 1-Tens of thousands rally in Pakistani capital, demanding PM quit
Supporters of ul-Qadri reach out for packs of biscuits, distributed for a breakfast, during the fourth day of their Revolution March in Islamabad
Supporters of Muhammad Tahir ul-Qadri, a Sufi cleric and the leader of political party Pakistan Awami Tehreek (PAT), reach out for packs of biscuits, distributed for a breakfast, during the fourth day of their Revolution March in Islamabad August 17, 2014. The leaders of two Pakistani protest movements, Imran Khan and ul-Qadri, vowed on Saturday to keep their protests alive until Prime Minister Nawaz Sharif resigns, after thousands entered the country's capital in the biggest challenge yet to the 15-month-old civilian government. REUTERS/Akhtar Soomro (PAKISTAN - Tags: POLITICS CIVIL UNREST)
Supporters of Muhammad Tahir ul-Qadri eat breakfast in the early morning during the fourth day of the Revolution March in Islamabad
Supporters of Muhammad Tahir ul-Qadri, a Sufi cleric and leader of the political party Pakistan Awami Tehreek (PAT), eat breakfast in the early morning during the fourth day of the Revolution March in Islamabad August 17, 2014. The leaders of two Pakistani protest movements vowed on Saturday to keep their protests alive until Prime Minister Nawaz Sharif resigns, after thousands entered the country's capital in the biggest challenge yet to the 15-month-old civilian government. REUTERS/Akhtar Soomro (PAKISTAN - Tags: POLITICS CIVIL UNREST)
A supporter of Khan, cricketer-turned-opposition politician, washes his face with water from a supply tank during their "Freedom March" in Islamabad
A supporter of Imran Khan, cricketer-turned-opposition politician and chairman of the Pakistan Tehreek-e-Insaf (PTI) political party, washes his face with water from a supply tank during the fourth day of their "Freedom March" in Islamabad August 17, 2014. Khan, who is leading one of two large anti-government demonstrations in the capital, has called on followers to show their strength on Sunday as he tries to force the government to resign. REUTERS/Akhtar Soomro (PAKISTAN - Tags: POLITICS CIVIL UNREST)
File photo of a family on a bike riding past a truck with pictures of Imran Khan, chairman of Pakistan Tehreek-e-Insaf (PTI) political party, and other party leaders, outside his residence before the start of today's Freedom March in Lahore
A family on a bike rides past a truck with pictures of Imran Khan, chairman of Pakistan Tehreek-e-Insaf (PTI) political party, and other party leaders, outside his residence before the start of Freedom March in Lahore in this file picture taken August 14, 2014. Pakistani opposition politician Khan, who is leading one of two large anti-government demonstrations in the capital, has called on followers to show their strength on Sunday as he tries to force the government to resign. REUTERS/Akhtar Soomro/Files (PAKISTAN - Tags: POLITICS CIVIL UNREST)
File photo of Imran Khan, chairman of Pakistan Tehreek-e-Insaf (PTI) political party, gesturing as he leads the Freedom March in Lahore
Imran Khan, chairman of Pakistan Tehreek-e-Insaf (PTI) political party, gestures as he leads the Freedom March in Lahore in this file picture taken August 14, 2014. Pakistani opposition politician Khan, who is leading one of two large anti-government demonstrations in the capital, has called on followers to show their strength on Sunday as he tries to force the government to resign. REUTERS/Mani Rana/Files (PAKISTAN - Tags: POLITICS CIVIL UNREST)
Pakistan protest leader Khan calls for show of strength
PAKISTAN-PROTESTS/ (PIX, TV):Pakistan protest leader Khan calls for show of strength
Pakistan anti-government protests draw determined crowd
PAKISTAN-POLITICS/ (PIX, TV,UPDATE 2):UPDATE 2-Pakistan anti-government protests draw determined crowd
A commando soldier patrols behind a barricade in Islamabad
A commando soldier patrols behind a barricade with flags left behind by supporters of the Pakistan Tehreek-e-Insaf (PTI) political party, near the venue of the Freedom March in Islamabad August 16, 2014. More than 20,000 anti-government protesters flooded the centre of Pakistan's capital on Saturday, vowing to stay in the streets until Prime Minister Nawaz Sharif resigns. REUTERS/Faisal Mahmood (PAKISTAN - Tags: POLITICS CIVIL UNREST)