A powerful bomb exploded early Friday at a religious gathering at a Muslim shrine in Islamabad, killing at least 19 worshipers and injuring dozens.
Ambulances took the dead and injured to nearby hospitals as security forces rushed to cordon off the scene of the blast. Officials have not confirmed eyewitness accounts that it was a suicide bombing.
The explosion occurred early Friday at the main compound of Bari Imam shrine on the outskirts of Islamabad. Several thousand mostly Shiite Muslims had gathered there to celebrate an annual festival.
One of the worshipers, Talib Rizvi, says many were injured by the bomb. "They [police] have taken over 60-70 injured and they were very, very seriously injured. It seems to be a suicide blast," he said. "They have taken one of the heads, which they feel is the head of the suspect."
Police have launched an investigation but have not made any arrests. It is unclear whether the attack is linked to rivalry between militant members of Pakistan's Sunni majority and its Shi'ite minority. The week-long annual celebrations attract thousands of Pakistanis from each of the Islamic sects to the Bari Imam shrine, but they hold separate services inside the main compound.
Many Shi'ite worshipers blamed authorities for not preventing the attack.
Islamabad's police chief, Talat Mahmood, dismisses these suggestions. "This [religious festival] thing has been going on for the last one week. The entire police force was here with all the officers," he said. "[But] if it is a suicide bombing, then you know how difficult [it should be] to stop a suicide bombing."
President Pervez Musharraf has condemned the attack as a terrorist act. Sectarian violence in Pakistan has claimed hundreds of lives in recent years.