Imphal, October 07: With the Government and NSCN(I-M) reaching a crucial phase in their peace parleys, the Centre has asked major Naga insurgent outfit to restrain its cadres by confining them to their camps or face action by security forces for violation of the mutually agreed ceasefire, official sources said today.

Centre�s warning comes in the wake of the arrest of 13 top-level NSCN(I-M) cadres in Manipur�s Senapati district last evening, including self-styled Home Secretary AK Lungalang and senior leaders K Chawang and David Pere.

The sources said the insurgent outfit has been advised to confine its cadres into the camps designated in the agreed ground rules of the ceasefire.

The ceasefire has been extended for a year after it expired on July 31.This is crucial for the peace process, the negotiations for which have now entered a "critical stage"; the sources said adding any violation of the ground rules of ceasefire could complicate matters at this delicate stage.

Meanwhile, in a statement faxed to PTI, the NSCN(I-M)�s Steering Committee Convenor VS Atem demanded immediate release of the 13 leaders arrested by the Manipur police saying the action was in violation of the ceasefire.

Atem also acknowledged in his statement that the peace process had entered a "crucial phase", but criticized what he described as "a deliberate attempt by the Manipur Government to sabotage" it.

Centre�s emissary K Padmanabhaiah had held extensive parleys with the top leadership of NSCN(I-M) in Amsterdam last month to iron out differences on the political process.

Though the two sides did not firm up a joint statement after the three-day talks from September 17, they decided to continue the dialogue process in November somewhere outside India, the sources said.

Padmanabhaiah, along with Intelligence Bureau Director KP Singh, met NSCN(I-M) chairman Isak Chishi Swu, general secretary Thuingaleng Muivah and other senior leaders including Raising, Puni Mao, Launga Lang and Q Ticcu last week and held "thorough" discussion on the "entire range of issues" aimed at ironing out major differences, the sources said adding that the NSCN(I-M) leadership raised 31 issues essentially relating to greater autonomy for Nagaland.

This was the second round of talks after Swu and Muivah visited India in January this year and held discussions with Prime Minister Vajpayee, his deputy LK Advani and several other political leaders.

The Centre, which entered into a ceasefire agreement with NSCN(I-M) in 1997, has extended the ceasefire for another year beyond July 31 this year.