Supporters of Pakistan's religious hardline Sunni Muslim party Jamiat Ulema Islam (JUI) shout slogans during a protest in Karachi on November 21
Pakistan on Friday boosted security across the country after Sunni Muslim groups called for protests against last week's sectarian violence in the garrison city of Rawalpindi that killed 11 people.
Clashes erupted in Rawalpindi, which neighbours the capital Islamabad, a week ago when a procession by Shiite Muslims to mark the most important day of the mourning month of Muharram coincided with a sermon at a nearby Sunni mosque.
The groups attacked each other, TV cameramen and security forces, firing gunshots.
Schools, shops and restaurants were closed in the city on Friday while roads were deserted in both Rawalpindi and Islamabad.
The government has deployed thousands of police and paramilitary troops in all major cities to maintain order, with the army on call in case of any violence, a police official in Islamabad told AFP.
He added that extra security arrangements have been taken for the protection of Shiite mosques.
"Extra police force have been deployed in the sensitive areas and around the Shiite mosques," the official said, requesting anonymity.
Police have used shipping containers to block certain roads in Islamabad and Rawalpindi, while the approaches to the diplomatic enclave, which houses foreign embassies, were sealed.
In the largest city Karachi, all shops, restaurants and gas stations remained closed and roads were deserted with heavy deployment of police and paramilitary troops, an AFP reporter said.
The protest call was given by Ahle Sunnat Wal Jamaat (ASWJ), a Sunni sectarian group and later supported by Wafaqul Madaris, which runs seminaries along with other Sunni groups including the Pakistan Ulema Council, a moderate body of Islamic clerics.
Demonstrations are expected after Friday afternoon prayers and prayer leaders are to speak about the violence in their sermons.
Umar Hayat Lalika, regional police chief for Rawalpindi told reporters that gatherings in the city have been banned and police would stop any attempts to hold rallies.