The police, on Sunday, released sketches of two suspects in the Malegaon blasts and said they had obtained some 'concrete clues', including that high intensity explosives were used in the four blasts on Friday.

"I have a team of 20 officers who are working on the case including specialists from the National Security Guard. We have got two to three concrete clues and we are working on those. The sketches we have released are based on eyewitness accounts," Inspector General of Police (Nasik range) P K Jain told reporters.

"There is no clarity on the kind of explosives used in Friday's blasts, and we are still awaiting the forensic report, but from the injuries sustained, where splinters have entered the bodies of the victims, we can deduce that high intensity explosives were used," Jain said.

"We have also gone to two shops where the cycles were bought. One cycle was used at the Bada Kabrastan blast site and the other in the blast at Mushaira Chowk," Jain said, adding that the shop owners were being questioned.

He said there are two aspects to the case - "One is interrogation of suspects and second is investigations where any person can help in the case."

Thirty-one people were killed and nearly 300 injured in the four blasts near Noorani mosque, a nearby graveyard and the busy Mushaira Chowk in Malegaon on Friday.

Jain appealed to the public to 'maintain peace and unity' so that police could concentrate on the investigation instead of using forces to maintain law and order.