The fighting between the soldiers and rebels of the separatist National Socialist Council of Nagaland took place in the thick jungles of Myanmar's northern Sagaing Division, the rebel leader said.

More than 300 Myanmar soldiers demolished one of their bases using mortars and heavy weapons, senior Nagaland separatist leader Kughalo Mulatonu told AFP by telephone from the India-Myanmar border.

"Our cadres fled the camp to safer areas and we have sent in reinforcements to fight the soldiers," he said. "We are using rocket-propelled grenades to counter the advancing soldiers."

There was no immediate confirmation by authorities in Myanmar.

The rebels are fighting for an independent tribal homeland in India's northeastern state of Nagaland, which borders Myanmar. The militants have at least at least 50 camps with around 7,000 rebels entrenched in fortified bunkers in Myanmar's thick jungles to evade Indian soldiers.

In December, Myanmar launched a massive military offensive backed by a brigade of around 3,500 government soldiers to evict Indian separatists based in Sagaing.

In an attack last month on rebel bases by Myanmar troops, 15 soldiers and six rebels were killed.

At least four other militant groups from India's northeast, where numerous tribal and ethnic groups are fighting for greater autonomy or independence, have camps in Myanmar.