Gunmen have attacked a prayer meeting in Pakistan, killing 15 people and wounding more than 20 others.

The victims included five children and a police officer.

Police have confirmed the deaths of 11 people but Shia Muslim leaders say 15 were killed in the attack.

Reports say that a group of Shia Muslims were holding a meeting in the village of Attock, some 150km north-west of the capital, Islamabad, when the gunmen burst in, firing automatic weapons and throwing grenades.

There is no clear indication who was behind the attack but one of those attending the meeting blamed rival Sunni Muslims.

'Insecure'

Sayed Mazhar Gailani, a leader of a Shia political party, Tehrik-e-Jaffria, called on the army to quickly arrests the assailants.

"People will feel insecure attending religious gathering until the killers are arrested," Mr Gailani said.

The attack, the worst of its kind for about a year, co-incides with the holy month of Muharrum, when devout Shias mourn the death of the grandson of the prophet Mohammed.

Last week, a prominent Shia leader, Waqar Hussain Naqvi, was shot dead in the southern city of Karachi.

Mr Naqvi was the secretary general of the Tehrik-e-Jaffria.

Pakistan's military ruler, General Pervez Musharraf, has called for an end to sectarian violence in Pakistan between the Sunni majority and Shia minority.