BANGKOK, April 7 (Aljazeera) - Thousands of people have fled across the border to Thailand amid fierce fighting between Myanmar’s armed rebel groups and the military, according to Thai officials.

Myanmar was plunged into turmoil when the military seized power from the elected government of Aung San Suu Kyi in February 2021, leading to mass protests and an armed uprising.

Thai officials said the fighting near the border was concentrated near the town of Myawaddy in southern Karen state, also known as Kayin, bordering Thailand’s Tak province.

“Around 3,998 people have fled into Thailand’s temporary shelter” across 10 areas, Tak provincial officials said in a statement, adding that the situation was being closely monitored. Thailand’s Khaosod English newspaper and BBC Burmese said fighting flared after an attack on a border guard post by armed fighters from the Karen National Liberation Army, an ethnic armed group.

“Many people crossed the border since yesterday and some are still also waiting on the Myanmar side to cross. People don’t have enough drinking water or any toilets for now,” a charity worker, who asked not to be named, told the Reuters news agency.

Since the coup, some ethnic armed groups such as the KNLA, which have been fighting the armed forces for decades, have joined forces with anti-coup groups to try and force the generals from power. Myanmar’s military has used lethal force against its opponents, killing some 3,212 people according to the Assistance Association for Political Prisoners and jailing more than 17,000.

It has also turned to air power in its bid to wipe out opposition, with observers accusing the military of targeting civilians in bombings and ground assaults. Entire villages have been burned to the ground. At least eight people, including children, were killed when their village in northwest Myanmar was bombed last week.

Myanmar’s military claims it is fighting “terrorists” and denies targeting civilians.

It blames anti-coup fighters for the deaths of civilians.