At least 47 soldiers were killed in over three days of fighting between government forces and Burmese rebels near Myanmar’s northeastern border, according to a report by the state-run Global New Light of Myanmar newspaper. Over 70 soldiers were also injured in what is possibly the heaviest fighting in the region in recent years.

The troops were killed in clashes in the Shan State, which borders China, with mostly ethnic Chinese rebels from the Kokang region fighting under the umbrella group named Myanmar National Democratic Alliance Army (MNDAA), the newspaper reported. The fighting reportedly broke out on Feb. 9.

“Acting on tips that a 200-strong Kokang renegade force was planning to attack a military headquarter in the Kongyan area, the government columns sent supporting troops to the region,” the newspaper claimed in its English-language edition. “So far, the fighting has left government forces with 47 dead, 73 wounded and five vehicles destroyed.”

The army also carried out airstrikes targeting rebel strongholds, the newspaper reported. As of now, it is not clear how many rebels were killed in the clashes.  

The resurgence of conflict, which comes after a six-year period of relative peace in the region, could derail efforts by President Thein Sein-led government to sign a peace deal with the Kokang rebel groups.

The MNDAA had signed a peace deal with the Burmese government in 1989. However, clashes broke out in 2009 over demands by the government that the rebels be assimilated into a national border guard force under a central leadership. The ensuing clashes resulted in the displacement of thousands of civilians, who allegedly fled to the Yunan province across the border in China.