Bangkok: Myanmar's military has clashed with militias controlled by the country's ethnic Kachin minority in a remote but strategic region where China is building hydropower plants.

The fighting, which began on Thursday, has killed at least four people and forced 2,000 more to flee, according to the US Campaign for Burma.

The rebels belong to the Kachin, one of Myanmar's sizable ethnic minorities.

Those groups have struggled for decades to win more autonomy, but their efforts have routinely been met by military suppression.

Kachin military commander Gwan Maw told US-funded Radio Free Asia on Tuesday that the fighting in northern Myanmar's Momauk region, near the Chinese border, could spread and possibly escalate into civil war if the government refused to negotiate an end to it with the Kachin Independence Organisation.

The 8,000-strong Kachin militia reached a peace deal with the country's former ruling junta in 1994, but the truce broke down last year after the militia rejected a call by the government to become border guards under army leadership.

The junta made the appeal ahead of last November's elections, Myanmar's first in 20 years, which paved the way for a new a civilian government to take over in March that critics say is a simply a proxy for continued military rule.

The Campaign for Burma, a Washington-based lobbying group that uses Myanmar's former name in its title, said hundreds of Myanmar government troops deployed to the northern region to force out Kachin forces after they refused to abandon a strategic base.