MULTAN, Pakistan (AFP) - Troops patrolled the streets of central Pakistan's Multan city as protestors hurled stones and clerics leading midday prayers condemned a car bomb attack that killed 41 Sunni Muslims a day earlier.
Around 200 people staged a demonstration in the center of this ancient "city of saints," pelting cars with stones and setting fire to tyres, but causing no injuries.
Multan was tense but otherwise calm a day after the bombing at a prayer vigal by 2,000 followers of outlawed Sunni extremist group Sipah-e-Sahaba, who were mourning the first anniversary of leader Azam Tariq's assassination.
The attack was the sixth outbreak of sectarian violence this year, bringing the death toll to 165.
Police, pararamilitaries and the army were on high alert throughout Pakistan to prevent revenge attacks or protests after Friday midday prayers.
Amid the nationwide high security alert, police guarded mosques as worshippers gathered for sermons.
"The government has directed the entire security apparatus to remain on a high state of alert, because of the threat posed by elements trying to destabilise the country through acts of terrorism," Interior Minister Aftab Sherpao announced after an emergency cabinet meeting late Thursday.
Prayer leaders appealed for calm and swift prosecution of the attackers, who have not yet been identified.
"We strongly condemn the terrorism attack and demand the government arrest the culprits," prayer leader Maulana Attaur Rehman told his congregation at the Jamia Rashidya mosque.
Most funerals were held Thursday afternoon, but Sunni leaders had declared Friday a day of mourning and called for protests after midday prayers.
The Pakistani cabinet has also declared a ban on religious gatherings, exempting only congregations in mosques.
"The federal government has decided to advise the provincial governments to impose bans on processions, religious gatherings and congregations until further orders, except for gatherings for prayers inside mosques," Sherpao told reporters after the meeting.
The car bomb attack was the second religious massacre in under a week, coming six days after 30 worshippers from the rival Shiite sect were killed by a suicide bomber during Friday prayers in eastern city Sialkot.
The latest attacks raise to 165 the number of people killed in six sectarian assaults this year, one of the highest levels in two decades of violence between Sunni and Shiite fanatics.
Shopkeeper Abdul Ghaffar feared the religious harmony advocated by the 11th and 12th century saints buried in Multan was being violated.
"Multan is a city of Sufi saints who preached peace and harmony among all human beings, and with such an incident, I fear that the seeds of destruction are being sown here," he told AFP.
At a funeral some 60 kilometers (37 miles) outside Multan, villagers hailed victim Qari Saeed Rehman, a religious student in his 20s, as a martyr.
"Our village is fortunate and blessed to have a martyred son," Muslim cleric Maulana Ataur Rehman told 300 mourners in his native village Choprahta.
The attack drew strong condemnation from United Nations Secretary General Kofi Annan, who expressed "serious concern" about the dangers of sectarian violence.
In Washington the State Department also condemned the bombing, saying that "attacking mourners during a condolence ceremony is a particularly despicable and cowardly act."
Pakistan's Sunni majority and Shiite minority for the most part live together peacefully but militants from each sect have mounted bitter tit-for-tat attacks on each other since the 1980s. The conflict has so far cost more than 4,000 lives.