Islamabad: At least three people were killed and several others injured in a bomb attack on a Shia mosque in Pakistan's garrison town of Rawalpindi Wednesday, a media report said. A splinter group of Tehreek-i-Taliban Pakistan (TTP) has claimed responsibility for the attack.

A spokesperson of Pakistan Institute of Medical Sciences said that two people were pronounced dead when their body was brought to the hospital. According to hospital sources, one more person succumbed to injuries later. The condition of five of the injured is reported to be critical, Dawn reported.

The report added that Jundullah, a splinter group of TTP, was behind the attack. A spokesperson of the militant group said the attack was a reaction to an anti-terrorist operation by the government forces in North Waziristan.

An initial investigation suggested that the explosion occurred when a suicide bomber detonated his explosives at a security check point at the Qasar-e-Sakina Imambargah on Kurri Road.

The mosque, located in the vicinity of the main highway linking the twin cities of Islamabad and Rawalpindi, was packed to capacity at the time of the explosion.

Police said the worshippers inside the mosque remained safe, as the casualties included the people who were at the entrance and deployed for the security of the imambargah. Security forces were rushed in to cordon off the area as rescue efforts were launched at the targeted site.

This was the fourth such attack targeting the Shia community in Pakistan this year. Last week, 21 people were killed in a suicide attack at a Shia mosque in Peshawar city during Friday prayers.