By Subir Bhaumik BBC correspondent in Calcutta

Leaders of India's longest-running separatist movement have welcomed a decision by the government in the north-east Indian state of Nagaland to withdraw legal cases against them.

The Nagaland state government this week withdrew charges against two senior leaders of the outlawed National Socialist Council of Nagaland, (NSCN).

These two leaders, NSCN Chairman, Issac Chisi Swu and General Secretary, TH Muivah, can now visit India to continue their negotiations with Delhi that have been going on for the past four years.

Two years ago, they were charged with masterminding an attack on the state's chief minister, SC Jamir.

The minister narrowly escaped and some of his police guards were killed.

'Positive step'

The NSCN's chief spokesman, Phungting Shimray, welcomed the decision to withdraw the cases against the two men.

Mr Shimray described the move as both a substantive political step and a welcome gesture in support of the on-going negotiations between the NSCN and the Indian Government.

NSCN leaders have always been suspicious of the chief minister's motives, accusing him in the past of supporting rival separatist factions.

Now Mr Jamir's government has not only withdrawn the cases against the NSCN leaders, but has also cancelled a reward announced earlier for their capture.

Earlier this year, Indian Prime Minister, Atal Behari Vajpayee, met the two NSCN leaders in Japan and invited them to come to India for further negotiations.

Manipur refuses

NSCN leaders said they could accept only if the cases against them in the north-eastern states were dropped.

While Nagaland has dropped the cases against the two NSCN leaders, the state government in Manipur has refused to do so.

A Manipur government spokesman said the NSCN must first stop what he described as rampant extortion, killings and kidnappings in the state.

But he did not make it clear whether Manipur would pursue the arrest of Mr Swu and Mr Muivah if they came to Delhi and Nagaland, but stopped short of visiting Manipur.