'Regrettably, we did not challenge the threat of Leftwing extremism adequately. Today, this poses a grave challenge. We are preparing to take on this challenge but the details cannot be disclosed,' the minister added.

'I have personally visited the (extremist-affected) states. We will be holding a meeting in August (to discuss the roadmap for taking on the extremists),' Chidambaram said, adding: 'We now have a military advisor to help us draw up our plans.'

Noting that the issue 'essentially has to be answered by the states as this is linked to the lack of development', he said the 'most recent manifestation of this' was in Lalgarh in West Bengal, where Maoists had declared a 'liberated area' till the security forces mounted a major offensive against them.

'The issue has to be tackled two-fold. First, there is police action to re-establish the writ of the state followed by developmental activities,' Chidambarm said.