A bombing at a Shiite mosque in the eastern city of Lahore on Sunday killed at least four people and injured others, officials said.
A witness said a man carrying a briefcase tried to enter the Husainia Hall mosque in the ancient walled part of the city during evening prayers but was blocked by security guards. He then detonated a bomb in the briefcase.
"Our two security guards were martyred and the suicide bomber was killed," said witness Sajjad Bhutta.
Punjab province Home Secretary Hassan Waseem was quoted as saying by the state news agency that four people were killed and others injured.
Private Geo television network said six injured were taken to hospital.
The bomb went off at the mosque at 5:40 p.m. after prayers, said Raja Basharat Illahi, the province's law minister. Dozens of people were inside the mosque when the blast went off, police said.
Information Minister Sheikh Rashid Ahmed immediately condemned the bombing.
The attack was the third this month against a religious target in Punjab, stoking fears of spiraling sectarian violence between Shiite and Sunni Muslims.
On Oct. 1, a suicide bombing at a Shiite mosque killed 31 people in Sialkot city, then six days later, a car bombing at a gathering of Sunni Muslim radicals in Multan city killed 40 people.
No group claimed responsibility for those attacks, which prompted authorities to ban religious gatherings across the country -- except for Friday prayers at mosques.
Adding to the tensions, on Saturday two prominent Sunni clerics were gunned down in the volatile southern city of Karachi, triggering riots by their followers.
Most Sunnis and minority Shiites live peacefully together in this Islamic country, but militants from both sects stage attacks.