The fighting with the Kokang rebels began Monday in the town of Laukkai, near the border with China, the state-run newspaper The Global New Light of Myanmar said.
It reported that 73 government troops had been wounded in the clashes between Monday and Thursday but didn't provide any information about casualties among the rebels or civilians.
The Kokang guerrilla forces "were found to be good at military maneuvering with the use of scores of heavy weapons including anti-aircraft machine guns," the report said.
Multiple ethnic groups in Myanmar are seeking greater autonomy. Violence continues to erupt in some of the long-standing conflicts despite government efforts to reach a peace agreement.
The state-run newspaper reported that government forces had used airstrikes as part of efforts to thwart the Kokang rebels' attempt to capture Laukkai. The situation in the town has since returned to normal, it said.
CNN couldn't independently verify the report's claims and was unable to reach a representative for the rebels.
The Kokang forces lost fighters and territory during offensives by the Myanmar military in 2009 but have regrouped since. The rebels haven't agreed to sign a nationwide peace agreement the government has pursued with armed ethnic groups.
Laukkai is in northern Myanmar's Shan state, where other ethnic minorities have also mounted resistance to central government rule.
Local media reported that fighters from at least two other rebel armies had joined forces with the Kokang guerrillas to take on the government troops.
The fighting in Laukkai this week drove some residents of the area across the border into China's Yunnan province, the Chinese Foreign Ministry said Tuesday.
"We hope that relevant parties in northern Myanmar can resolve their differences via continuing to uphold peaceful talks and prevent the clashes from escalating and affecting border stability," Hua Chunying, a spokeswoman for the Chinese Foreign Ministry, told reporters.