After a lull of several months, Srinagar [Images] was rocked by a massive explosion in which at least 17 persons were injured, one of them critically.

The police said militants carried out the powerful explosion on the city's only flyover in Jahangir Chowk, adjacent to city centre Lal Chowk on Wednesday evening.

The explosion in the high security area shattered the concrete of the fly-over sending splinters all around.

A portion of the flyover has been massively damaged.

"We are ascertaining whether the explosion was caused by a pre-planted IED (Improvised Explosive device) or whether it was a car bomb explosion," said the deputy inspector general paramilitary central reserve police force (CRPF) M.P.Natheal.

All the 17 injured persons including a woman were evacuated to city's SMHS hospital, where attending doctors described the condition of one of them as serious.

The explosion occurred outside the state High Court complex and close to the civil secretariat and the state legislature complex.

"The blast was massive. I saw splinters flying all around shattering the show windows of dozens of shops here. I ducked under the counter of my shop. This has happened here after many months. Peace in Kashmir is fragile. I am closing early to return home," said Abdul Rashid, a shopkeeper in the area.

The blast led to heavy panic in Jahangir Chowk which is also the city's busiest traffic crossing.

The blast came after several months of lull in capital Srinagar and amidst assertions by the authorities that the striking power of the militants had been largely undermined because of the successful operations carried out against them and the cross border infiltration into the state being lowest this year.

No group has yet claimed responsibility for the blast.

Senior police and paramilitary officers are present at the spot and forensic teams are scanning the area for evidence.