Pakistan is suspending phone coverage in many cities this weekend, an important one in the Shi'ite Muslim calendar, after a series of bomb attacks on Shi'ites triggered by mobile phones, Reuters said.

Hardline Sunnis have threatened more attacks as the Shi'ite mourning month of Muharram comes to a climax. More than a dozen people have already been killed this week attending Muharram processions.

"All the blasts that occurred in the last 15 days were mobile phone-based," Interior Minister Rehman Malik told reporters on Friday, November 23.

Intelligence information indicates more attacks have been planned for the coming days in the capital city of Islamabad, Karachi and Quetta. Mobile phone service will be suspended for hours in the three cities and dozens of others over the weekend.

In Karachi, more than 5,000 police are expected to patrol the streets during Muharram events over the next two days, with hundreds more on alert.