
The outbreak of violence came after days of peaceful demonstrations in Pakistan against the release of a video mocking the Prophet Muhammad. Pakistani officials had increased security in all major cities before Friday Prayer services, which have in the past served as flash points for protests, and until Sunday, calm had prevailed. The American Embassy here said in a message posted Sunday evening on Twitter that "all American personnel are safe and accounted for at U.S. Consulate, Karachi."
"The United States government has absolutely nothing to do with this video," another Twitter message by the American Embassy said. "We reject its content and its message."
Karachi is Pakistan's commercial capital, and the sprawling city is frequently torn by ethnic and sectarian violence. "Things usually get out of hand in Karachi," Mehreen Zahra-Malik, an assistant editor at The News International, said in an interview.
The demonstration on Sunday was spearheaded by two groups of Shiites, a minority in Pakistan, which had urged demonstrators to march "toward" the American Consulate.
The police responded by blocking the road that leads to the American Consulate with concrete barriers and shipping containers on Sunday afternoon. Then, as the march neared, the police fired tear gas canisters into the crowd. That failed to contain waves of angry demonstrators, who grew increasingly agitated, witnesses said.
The police and Rangers, a force controlled by the Interior Ministry, then fired shots into the air as demonstrators rushed through the clouds of tear gas, trying to reach the outer boundary wall of the heavily fortified consulate building. Water cannons were also used on the protesters, who began hurling stones.