Acknowledging the advantages the terrorists have in choosing their targets and claiming that it was not possible to protect each of them, Prime Minister Manmohan Singh on Friday described the internal security situation as difficult but asserted that the government was firm to uproot the menace.

A day after the blast at sufi shrine of Khwaja Mohiuddin Chisti in Ajmer, the Prime Minister said, ?We have to mobilise all resources and will power for complete defeat of terror machines.?

Singh was asked to comment on increasing terror strikes in the country and whether home minister Shivraj Patil was not capable of handling the situation and should step down.

The Prime Minister asserted that there was no lack of firmness of purpose when it came to dealing with terrorist acts. Describing the situation as ?difficult?, he said, ?I would not say that we should despair?.

He said it was time to think differently about the strategy on dealing with terrorism in future. ?But let there be no mistake about our resolve to meet this challenge head on,? he added.

Meanwhile, Harkat-ul-

Jehadi Islami, a Bangladeshi militant outfit, was suspected to be behind the Thursday?s blast in Ajmer in which a mixture Tri-Nitro Toluene (TNT) was used as the explosive material, sources in the security agencies said.

Informing reporters here that a special investigating team (SIT) had been constituted by the Rajasthan government to go into blast, home secretary Madhukar Gupta said, the SIT would interact with central security agencies to go into the bottom of the incident, which, he said was aimed at disturbing communal harmony.