NEW DELHI: Visiting those injured in the Samjhauta Express blasts, Prime Minister Manmohan Singh on Tuesday said the incident was an act of terror aimed at disrupting the Indo-Pak peace process and underlined that the two countries will not allow the "nefarious" designs to succeed.

Singh told reporters that the best tribute to the victims of Samjhauta Express explosions would be to remain "steadfast in commitment" to normalise relations between the two countries.

"All that I can say at this moment is that this was a heinous crime and we will make effort to bring to book those who are responsible for this crime," he said after visiting the injured people at Safdarjung Hospital.

"It is an act of terror designed to interfere and disrupt the peace process between India and Pak which is moving satisfactorily," Singh said.

He said it is a "solemn resolve of both the government of India and the government of Pakistan that we will not let these nefarious designs of terrorists to succeed."