"We are working toward an agreed framework. Five or six points, the more difficult points are settled. What is important is that areas of convergence are increasing. But areas of divergence remain. Tawang, in Arunachal Pradesh state, remains the most important," Narayanan, also the Special Representative to the India-China boundary talks said.

"Till that (the issue of Tawang) is settled whatever else we may do, it is difficult to say we have crossed the rubicon," Narayanan said in an interview to Straits Times of Singapore.

He said "when they (the Chinese) talk in terms of movement forward, they keep arguing Tawang has always been a part of Tibet, which is a matter of debate."

Tawang, nestled among the mountains in Arunachal Pradesh has long been a serious bone of contention between India and China.

He noted that the two sides have an agreement worked out in 2005 that areas of settled populations were not negotiable.

"Tawang is an area with substantial settled populations. Not a small number. It flies in the face of guiding principles and political parameters (for China to demand it). How we work out.. whether I have the ingenuity or Mr Dai (Bingguo, the Chinese Special Representative) has the flexibility, we will see," Narayanan said.

Though he dismissed reports that the boundary talks have "gone cold," Narayanan acknowledged that he could not hold talks with Dai during the last six months.