Pakistan has boosted security across the country after Sunni Muslim groups staged protests against last week's sectarian violence in the city of Rawalpindi that killed 11 people.
Schools, shops and restaurants were closed on Friday while roads were deserted in both Rawalpindi and Islamabad, the capital.
Extra police force have been deployed in the sensitive areas and around Shia mosques.
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 the AFP news agency, adding that security had been beefed up.
"Extra police force have been deployed in the sensitive areas and around the Shia 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.
The protests follow clashes which erupted in Rawalpindi a week ago when a procession by Shia Muslims to mark the most important day of the mourning month of Muharram coincided with a sermon at a nearby Sunni mosque.
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.
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 began after Friday afternoon prayers and prayer leaders were 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.
Source: Al Jazeera and agencies