At least 15 people have been killed in Pakistan in clashes during protests over an anti-Muslim film.
Police fired tear gas and live ammunition at thousands of demonstrators who threw rocks and set fire to buildings. Dozens were injured.
Muslims also marched in at least a half-dozen other countries, with some burning American flags and effigies of US President Barack Obama.
Pakistan has experienced nearly a week of deadly protests over the film, Innocence of Muslims, that has sparked anti-American violence around the Islamic world since it emerged on the internet in the past 10 days.
The deaths of at least 45 people, including the US ambassador to Libya, have been linked to the violence over the film, which was made in California and denigrates the Prophet Mohammed.
The Pakistani government declared today to be a national holiday - "Love for the Prophet Day" - and encouraged peaceful protests.
The US Embassy spent 70,000 dollars (£43,000) for advertisements on Pakistani TV that featured Obama and Secretary of State Hillary Clinton denouncing the video.
The deadliest violence occurred in the southern port city of Karachi, where 12 people were killed and 82 wounded, according hospital officials.
Armed demonstrators among a crowd of 15,000 in that city fired on police, according to police. The crowd also burned two cinemas and a bank.
Three people were killed and 61 wounded in the north-western city of Peshawar, where police fired on rioters who set fire to two cinemas and the city's chamber of commerce, and damaged shops and vehicles. Police and stone-throwers also clashed in Lahore and Islamabad, the capital.