Prime Minister Manmohan Singh [Images] on Wednesday stopped short of blaming terrorist groups in Pakistan for Tuesday's attack in Ayodhya, but said there was no doubt that the terror infrastructure was by and large intact.

In a blunt warning, Dr Singh said the recurrence of such incidents could derail the Indo-Pak peace process, which the two countries have committed to make irreversible.

• 6 militants storm Ayodhya, killed

"All those who are concerned have an obligation," Singh told reporters accompanying him to London [Images] for the G-8 summit at Gleneagles in Scotland.

"The terror attack at the makeshift Ram temple in Ayodhya was a major incident and there was no doubt that the infrastructure for terrorism (in Pakistan) is by and large intact," Singh, who has since arrived in London, said.

"Both President Pervez Musharraf [Images] and I have committed ourselves in the joint statement to make the peace process irreversible. I sincerely hope the comitment is honoured. The major element in this is that terrorism should be under control," Singh said.