ISLAMABAD: A powerful explosion at a shrine on the outskirts of the federal capital on Friday night injured at least 61 people, seven of whom are said to be in critical condition, DawnNews reported.

The blast took place at a shrine in the Pandorian area during commemoration of the death anniversary of local Sufi saint Baba Nangay Shah on the outskirts of Islamabad.

Chief Commissioner Islamabad Jawad Paul told Dawn.com that 54 people were injured in the blast. He said 34 were taken to Pakistan Institute of Medical Sciences (Pims) hospital where four are in critical condition, Nine are being treated in Benazir Hospital and 11 are shifted to Poly Clinic Hospital.

Number of injured increased to 61after seven more wounded persons were admitted in Pims hospital.

Locals, however, put the number of injured much higher at 70 to 80.

The likely terrorist attack took place on second day of the three-day annual Mela (festival).

The nature of the blast could not yet be verified but Chief Commissioner Paul told Dawn.com that initial probe into the incident suggests it was carried out through a time device as the bomb was likely planted inside a tree at the shrine.

Eyewitnesses told DawnNews that the explosion took place when food was being distributed amongst devotees.

An emergency has been imposed at Pims and Poly Clinic hospitals of the city where injured were taken to after the incident.

Dr Aisha of Pims hospital said earlier that 31 people were brought to the hospital out of whom four were critically injured.

Dr Khurram, an official at Poly Clinic Hospital, said that there were three critically injured people among the eight brought to the hospital.

According to a spokesman of Islamabad Police, security has been put on red alert at all entry and exit routes of the capital.

He said that after cordoning off the site of the incident, police, Rangers and Army commandos have launched a search operation to nab the culprits.