A shootout in a mosque in south-western Pakistan, caused by a dispute over who should lead prayers on one of Islam's most important holidays, has left 18 people injured, police said today.

Followers of the two rival religious leaders pulled out weapons and began shooting after arguing over which one should start Eid al-Adha prayers at a small mosque in the Khuzdar district of Baluchistan province, Javed Ahmed, a police official, said.

Khuzdar is about 550 miles south-west of Islamabad. Many of the region's ethnic Pashtuns carry rifles.

Millions of people throughout Pakistan have been peacefully celebrating Eid al-Adha. The three-day festival – known as the Feast of the Sacrifice – involves the slaughter of sheep and cattle in remembrance of Abraham's near-sacrifice of his son.

Pakistan began the religious holiday a day later than many other countries because of local authorities' interpretation of when the new moon was sighted.

Many mosques have increased security measures to guard against attacks by the Taliban and other Islamist extremists.

Earlier this month, at least 70 people died when a suicide bomber targeted a mosque frequented by anti-Taliban elders and a grenade exploded at another place of worship in Pakistan's north-west.