Burmese ethic media say fighting that began last week in Kachin state between government forces and Kachin rebels has now spread into Shan state.

The Kachin News Group reported that two battalions of the ethnic Kachin Independence Army have been engaged with Burmese forces since Tuesday evening in northern Shan state. It said the fighting continued Wednesday.

The Shan Herald, representing the Shan ethnic group, reported that about five government battalions were moving against the headquarters of the Shan State Army, also in Shan state.

The Thailand-based Kachin News Group said that in Kachin state, KIA forces had triggered land mines damaging three bridges and clashed with government forces near a strategic hydroelectric dam on the Shweli River.

The news group also said a former Kachin military leader and a representative to the national parliament have been placed under house arrest in the Kachin state capital, Myitkyina.

It named the two as Zahkung Ting Ying, former leader of the dissolved New Democratic Army-Kachin, and Waw Lau, the group's former military chief of staff. It said both continue to wield influence over Kachin forces in the field.

Campaign for Burma, a Washington-based advocacy group, said Tuesday that four Kachin fighters and at least 16 Burmese soldiers have been killed in the clashes. The group said about 2,000 Burmese villagers have fled their homes, most of them crossing the border into China.

The clashes with Burma's Kachin minority have been centered in a region where China is building hydropower plants near the Chinese border. The last 30 of some 100 Chinese engineers working on two hydropower plants and dams were permitted to leave Tuesday, bringing the operations to a standstill.

Burma's officials have not made any statements regarding the clashes. It is almost impossible for outsiders to confirm reports about the fighting. The border areas are largely off limits to foreigners and journalists.

The Kachin Independence Army, like several other ethnic militias in Burma, signed a cease-fire agreement with the central government several years ago. But those agreements began to break down in 2009, when Burma demanded that the militia groups come under central authority and serve as part of a national border guard. That prompted some militias to resume fighting.