The BBC said Myanmar troops attacked a Kachin base near Laiza, which is near the Chinese border in the northern area of Myanmar. Hundreds of government troops hit the base with mortar and artillery fire.
If the base falls, it will likely be easy for the Myanmar military to take Laiza, which would likely force thousands of civilians to flee, the BBC said.
The Kachin Independence Army, the only major ethnic group that hasn't signed a long-term cease-fire with the government, are fighting for ethnic Kachins to take greater control of northern Myanmar.
Although the Myanmar government has pledged to resolve the conflict, the army began a new offensive last month.