Twenty-five people were killed and more than 50 injured on Friday in a suspected suicide bombing at a Sufi shrine near the Pakistani capital, where hundreds of devotees had gathered for the Friday prayers and to celebrate an annual religious festival.

The blast took place around 11.20 am local time at the Hazrat Bari Imam shrine, devoted to Sufi saint Shah Abdul Latheef Khazmi, on the outskirts of Islamabad.

Local Geo TV reported that 25 people were killed, though officials put the number of dead at 19.

Of the 50 injured, the condition of five was stated to be serious. State-run PTV put the toll at 14.

Eye-witness accounts said a powerful bomb was detonated by a person in the crowded compound of the shrine, frequented by devotees from both Shia and Sunni communities.

Tariq Ali, a survivor, told reporters he saw a man tossing a 'bomb' into a thick crowd of people. He said he saw several bodies tossed into the air as the bomb exploded.

He said the person who threw the bomb too was killed and pointed to a severed head of a male lying on the
ground.

Initial reports had said the blast was caused by a remote controlled device.

Other eyewitnesses said a person got on to a stage set up by Shia devotees in the compound and blew himself up.

Pakistan Information Minister Sheikh Rashid Ahmed, however, said the claims of suicide bombing were yet to be ascertained.

The government declared a state of emergency in the main hospitals at Rawalpindi and Islamabad.

Angry survivors clashed with police protesting lack of security at the shrine.

There were no immediate leads yet on who caused the blast, but it coincided with the nation-wide protests called by the
Islamic alliance, Muttahida Majlis-e-Amal to protest the alleged desecration of Quran by US security personnel at
Guantanamo Bay detention centre.