A supporter of Tahir ul-Qadri, Sufi cleric and opposition leader of political party Pakistan Awami Tehreek (PAT), hides behind a tree as riot police release tear gas in Islamabad August 31, 2014. Pakistan has been shaken by weeks of anti-government demonstrations, with violence erupting late on Saturday after thousands tried to march on Pakistan's Prime Minister Nawaz Sharif's residence, prompting police to fire tear gas to stop them. REUTERS/Zohra Bensemra (PAKISTAN - Tags: POLITICS CIVIL UNREST)