By Subir Bhaumik
BBC News, Calcutta
The Indian military has begun airlifting essential goods to the north-eastern state of Manipur.
The NSCN wants a greater Nagaland
Organisations representing Naga tribesmen have been blockading a national highway for more than two weeks now.
They are demanding that some parts of Manipur be integrated into the neighbouring state of Nagaland.
The federal government has rejected the idea saying it is opposed by Manipur's political parties.
Last weekend local police tried to break the blockade by force, but the Nagas responded by burning down government buildings in four districts of Manipur where they are in a majority.
Loaded with essential commodities like medicines and foodstuff, at least four military cargo aircrafts started flying regular sorties into Imphal, the capital of Manipur.
Military officials say there is not enough space for landing the four aircraft simultaneously at Imphal airport, so only two aircraft were landing at any one time.
They say the aircraft are each carrying 10 tons of life saving drugs and other essential commodities which are urgently needed in the state.
The cost of transporting the goods will be borne by the Indian home ministry, a senior official in the Manipur government said.
Troops of India's Madras Regiment are camping inside the Imphal airport complex to offload the supplies and take them to secure areas.
Meanwhile, the government of Manipur is upgrading the bridges on another highway that connects the state with Assam.
Once that happens, all heavy trucks headed for Manipur will be able to use that highway rather than the one that passes through Nagaland and Naga-areas of northern Manipur.
Naga organisations set up roadblocks all along the highway that goes into Manipur from Nagaland, a road that formed the backbone of Allied defences against the Japanese drive into India during the World War II.
The blockade has now gone on for 15 days.
The Nagas in Manipur demand that four districts, mostly inhabited by people of the Naga tribes, should be integrated with the neighbouring state of Nagaland, a demand put across by the Naga rebel group, National Socialist Council of Nagaland ( NSCN).
The NSCN has threatened to call off negotiations with the Indian government unless Delhi concedes this demand. But the Indian government says all political parties in Manipur are opposed to parcelling off their territories to Nagaland.
The state witnessed massive violence and arson four years ago when angry Manipuris took to the streets to protest against an extension of the ceasefire between the NSCN and Indian government to the state of Manipur.