Hundreds of Pakistanis took to the streets on Tuesday to protest the Israeli commando raid on a Gaza-bound aid flotilla that left nine peace activists dead, DPA reported.
The protestors demanded that three Pakistanis who accompanied the mission be repatriated by Israel, which seized control of the vessels Monday and took them to an Israeli port.
The biggest rally was in Karachi where protestors chanted "Death to Israel" and called on the United States "to stop patronizing" the Jewish state.
Television footage showed police using water cannon, tear gas and batons to disperse the protesters when they tried to march towards the US consulate and the residence of the governor of Sindh province, of which Karachi is the capital.
The protestors pelted the police with stones, before at least six of them were taken into custody.
Rallies were also held in the capital, Islamabad, the eastern city of Lahore, Multan in central Pakistan and Quetta in the south-west, as well as in smaller towns across the country.
Earlier, Pakistan condemned the use of "brazen force" by Israel on the aid ships. Interior Minister Rehman Malik said the three Pakistanis with the mission were safe and the government was trying to bring them back.