BBC News Online: World: South Asia

Pakistan steps up security

The measures come just days before a special day of celebration to mark the Muslim holy month of Moharram.

Special armed-response units have also been deployed.

"We have sought the assistance from the military because there are too many flashpoints in the country and police cannot man all sensitive areas," Lahore police official, Tariq Dogar said.

Pakistan's Interior Minister, Moinuddin Haider, has said the government would consider banning some sectarian groups, if there was continued violence.

Day of mourning

Correspondents say sectarian tensions are high in Pakistan during this period, as devout Shias mourn the death of the grandson of the prophet Mohammed, Imam Hussein.

Sunday marks the 10th day of Moharram and Shias traditionally form processions in which they beat their chests and whip themselves in grief at Hussein's death.

Correspondents in Balochistan, meanwhile, have reported the discovery of a bomb in the provincial capital, Quetta.

The device was detected and defused.

Another report said Sunni and Shia followers clashed in the Pakistani city of Khanpur, attacking each other with bamboo sticks and iron bars.

Police used tear gas and fired into the air to break up the brawl.

Shia leaders have blamed Wednesday's attack on a Shia prayer meeting on Sunni extremists.

It was the first major instance of sectarian violence since General Pervez Musharraf seized power last October.