Critics say the Indian government has been slow to wake up to the threat posed by the Maoist or "Naxal" rebels, whose insurgency is killing people almost every day and has spread to huge swathes of the country's rural south, centre and east.

On Friday, Home Secretary V.K. Duggal tried to downplay the threat, but warned against complacency.

"The broad impression is that this violent Naxal movement is by and large under control," he said after a meeting of top officials and police chiefs from 13 affected states.

"But it has the potential to grow unless continuous effective steps, as are enshrined in policy, are not pursued."

On April 13, Singh will step in to chair a quarterly meeting of chief ministers from the 13 affected states, usually presided over by the country's interior minister.

Manmohan yesterday also ruled out any discussions with the insurgent outfit Ulfa in Assam on the issue of sovereignty.

Manmohan asserted that there would be no changes in the territorial structure of northeastern states without their consent.

"The question does not arise. We are all servants of the Constitution of India and the Constitutional position is quite clear on this," Singh said when asked whether the government would hold talks with Ulfa over its sovereignty demands.

"If Ulfa wants to talk they are open to raise any issue they want but that does not mean all issues are open for negotiations," the prime minister added.

Asked about the perception that there were differences between the Centre and the state on tackling the Ulfa problem, he said, "we want peace to prevail. We want to ensure that the state develop in an atmosphere of peace and tranquillity."

With tensions along the border with Pakistan easing and separatist insurgencies in India's restive northeast "somewhat under control", the prime minister's attention had turned to the Maoist problem, Duggal said. "Obviously it a matter of concern."

Duggal said 157 people had been killed in Maoist-related violence this year, up from 114 in the first quarter of 2005, driven by a jump in civilian deaths in the central state of Chhattisgarh.