Continuing sectarian violence in Pakistan has left more than twenty people dead since yesterday Friday.

Most of the victims have been Shi'ite Muslims.

They've been killed in different parts of the country, in what the BBC Islamabad correspondent says looks like a coordinated campaign.

The worst incident took place in Karachi -- nine Shi'ite Muslims were killed there as they said their morning prayers in a mosque. There have also been killings in Multan, Peshawar and Lahore, with gunmen firing automatic weapons before escaping on motorcycles. Members of the Shi'ite community have accused a hardline Sunni group Sipah-e-Sahaba of the attacks, but the group has denied this.

Our correspondent in Islamabad says these latest attacks are likely to force the authorities to consider launching a nation-wide security operation.