The proscribed United Liberation Front of Asom has been triggering blasts in Assam with uniform regularity setting off seven explosive devices, including five in Guwahati this month, killing nine persons and injuring 100 others.

The insurgent outfit also made an abortive bid to explode another bomb during the month in the city.

The ULFA on Saturday triggered a powerful bomb explosion concealed inside an autorickshaw near the Marwari Maternity Hospital at the commercial Athgaon area, killing seven persons and injuring 30 others. On May 18, the ULFA set off a bomb in adjacent Fancy Bazar injuring 20.

The local people, irked over the frequent blasts in the area, came out in thousands to stage a violent protest on Saturday alleging police failure to provide security. The business community suspected that some ULFA members, in an attempt at land-grabbing in the prime commercial area of Fancy Bazar and nearby Athgaon, were triggering blasts to create a fear psychosis.

Athgaon has witnessed blasts carried out by ULFA twice earlier when on May 6, 19 persons were injured and on May 14, two persons were killed and eight others injured.

Earlier on May 3, the ULFA exploded a bomb in the premises of the Food Corporation of India godown in Guwahati injuring two of its employees. On May 10, seven persons were injured in Upper Assam's Sibsagar town when one of ULFA's women cadres left a bag containing an explosive device inside a pathological centre.

On May 21, the banned outfit injured 14 persons in a powerful bomb explosion in Lower Assam's Bongaigaon district.