The Kachin Independence Army (KIA) and its allies say they are attacking Myanmar junta positions in the jade-mining hub of Hpakant Township in Kachin State.
The KIA says it attacked junta troops and police in Hsengtaung village in Seikmu village tract on Tuesday night.
Villagers said they are trapped in their homes.
Analysts have reported a buildup of anti-regime forces in Hpakant Township, sparking fears of indiscriminate junta airstrikes and shelling.
A pastor in Hpakant said civilians cannot escape the conflict as nowhere is safe.
“Everywhere is on alert and there are no volunteers or organizations to help,” he told The Irrawaddy.
On Monday, a major junta hilltop in Tar Ma Khan village in the township was attacked and seized on Tuesday.
Around 15 junta troops were apprehended along with arms and ammunition and the village police station was burned down, according to resistance fighters.
A KIA source said: “We are now attacking a large hilltop outpost held by Light Infantry Battalion 119. The junta is using airstrikes to defend it.”
Hpakant residents reported repeated junta shelling on villages around the township, which is famous for its enormous jade mines and as the source of the vast majority of the world’s imperial jade.