Pakistani demonstrators react beside burning tyres as they block a main highway during a protest against an anti-Islam film in Rawalpindi on September 21, 2012.

Pakistani demonstrators react beside burning tyres as they block a main highway during a protest against an anti-Islam film in Rawalpindi on September 21, 2012.

A Pakistani demonstrator throws a tear gas shell towards riot police during a protest against an anti-Islam film in Islamabad on September 21, 2012.

Pakistani demonstrators throw stones toward the police during a protest against an anti-Islam film in Islamabad on September 21, 2012.

Pakistani demonstrators attack an empty police post as they attempt to reach the US embassy during a protest against an anti-Islam film in Islamabad on September 21, 2012.

A Pakistani protester, center, pushes a burning tire as others run away to avoid tear gas fired by riot police during clashes erupted as protestors tried to approach the US embassy, in Islamabad, Pakistan, Friday, Sept. 21, 2012.

A protester holds a stick as he shouts anti-American slogans in front of a burning cinema during an anti-US protest rally to mark the “Day of Love” in Peshawar September 21, 2012.

Pakistani demonstrators attack a cinema during a protest against an anti-Islam film in Karachi on September 21, 2012.

Pakistani demonstrators are pictured in front of a burning cinema during a protest against an anti-Islam film in Karachi on September 21, 2012.

Pakistani demonstrators look on in front of a burning cinema during a protest against an anti-Islam film in Karachi on September 21, 2012.

A masked Pakistani demonstrator walks past burning police vehicles during a protest against an anti-Islam film in Karachi on September 21, 2012.

Smoke and flames rise from burning police vehicles torched by angry demonstrators during a protest against an anti-Islam film in Karachi on September 21, 2012.

A Pakistani demonstrator brandishes a stick near burning police vehicles during a protest against an anti-Islam film in Karachi on September 21, 2012.

A Pakistani demonstrator carries material inside a burning cinema during a protest against an anti-Islam film in Peshawar on September 21, 2012.

Pakistani demonstrators topple a freight container, placed by police to block a street during a protest against an anti-Islam film in Lahore on September 21, 2012.

Pakistani demonstrators vandalise machinery during a protest against an anti-Islam film in Peshawar on September 21, 2012.

Pakistani demonstrators throw their shoes towards a portrait of Florida pastor Terry Jones (C) during a protest against an anti-Islam film in Lahore on September 21, 2012.