Myanmar villagers arrive at an evacuation area after fleeing to Thailand following clashes between Myanmar troops and an ethnic Karen rebel group Friday, Dec. 17, 2021, in Mae Tao, Tak province, northern Thailand. Fighting between Myanmar government forces and ethnic guerrillas has sent about 2,500 villagers fleeing across the border into Thailand, a Thai army officer said Friday. (AP Photo/Chiraunth Rungjamratratsami)

BANGKOK (AP) — Fighting between Myanmar government forces and ethnic guerrillas has sent about 2,500 villagers fleeing across the border into Thailand, a Thai army officer said Friday.

The exodus was the biggest since April, when several thousand villagers from Myanmar’s eastern state of Karen fled to Thailand following airstrikes by Myanmar government forces in territory held by the Karen ethnic minority. They were allowed to stay for a few days then returned to Myanmar.

The Karen are one of several ethnic minorities who have been battling for decades for greater autonomy from Myanmar’s central government. Fighting between the two sides is intermittent, but heated up after the military in February seized power from the elected government of Aung San Suu Kyi.

A Thai army officer in the western border province of Tak told The Associated Press that around 2,500 villagers from Myanmar had crossed the Moei River, which marks the border, since Thursday to seek shelter in Thailand’s Mae Sot district.

The officer, who spoke on condition of anonymity because he is not authorized to release information, said Thai authorities provided the evacuees -- mostly women and children -- with humanitarian assistance including shelter and food, and tested them for COVID-19.

The Thai army task force responsible for border security issued a warning Thursday through the joint Thai-Myanmar Border Committee that it was prepared to retaliate if stray artillery shells landed on Thai soil. At least one shell landed Thursday on a Thai sugarcane plantation, causing a small fire.

The fighting earlier this year tailed off when the rainy season started, but with the rains mostly over, is expected to resume, not only in Karen territory but also in areas controlled by other ethnic rebel groups.

This week’s clashes were triggered by a raid on Tuesday by government soldiers on the town of Lay Kay Kaw, which is in territory under the de facto control of the Karen National Union, or KNU, the civil authority for the area.

Independent Myanmar media reported govermment troops seized 30-60 people associated with the organized opposition to the military government, including at least one elected lawmaker from of Suu Kyi’s National League for Democracy party. The KNU has allowed opponents of the military-installed government to take refuge in its territory.

The Karen, along with other ethnic minority groups, have a loose alliance with the army's foes, who have established a self-styled alternative administration, the National Unity Government, and its armed wing, the People's Defense Force, which is a conglomeration of lightly armed local self-defense groups.

According to a KNU statement, its armed guerrillas did not attack the government soldiers on Tuesday because it would have endangered the town’s residents, but fighting broke out on Wednesday when the soldiers returned, and shelled Karen guerrillas.

It said fighting escalated Thursday when the government sent reinforcements to the area, including units of the Border Guard Forces. Some 4,000 people had fled the town, it said.

The Karen claimed to have killed or captured more than a dozen troops, and circulated photos of their prisoners.

Lay Kay Kaw enjoys unique status as a settlement established to promote reconciliation. It was built in 2015 with financial support from Japan’s Nippon Foundation to house and educate people fleeing from decades of combat, especially refugees returning from Thailand.

News from © The Associated Press, 2021