Little-known Islamic Security Force-Indian Mujahideen [Images] on Friday claimed responsibility for the serial blasts that killed 77 people in Assam and warned of more such attacks.

In an SMS message sent to local News Live television channel, the ISF-IM claimed responsibility for Thursday's blasts and threatened to carry out more bomb explosions in several parts of the country.

The message said, "we thank all our holy members and partners" for successfully carrying out the task.

The SMS was received on the mobile of the channel's input desk from a Reliance [Get Quote] connection with the number 9864693690.

The mobile phone was subsequently switched off and security forces traced it to Moirabari in central Assam's Nagaon district registered in the name of one Nazir Ahmed.

Police officials are investigating the matter.

The outfit was formed in 2000 in Lower Assam's Bodo-dominated areas "to counter" the Bodo Liberation Tigers and NDFB militants, police sources said.

The full text of the SMS is:

"We, ISF-IM, take the responsibility of yesterday blast. We warn all of Assam and India for situation like this in future. We thank all our holy members and partners. AAamin."