Thailand scrambled fighter jets near its border with Myanmar on Thursday and ordered its defence attache to issue a warning to the military government, its air force said, over what it called an airspace violation during a combat operation.
Two F-16 fighter jets were deployed when radar detected a plane in Thai airspace in Tak province close to the Myanmar border on Thursday, which was carrying out attacks on ethnic minority rebels, air force spokesperson Air Vice Marshal Prapat Sonjaidee said in a statement, news agency Reuters reported.
Thai Prime Minister Prayuth Chan-ocha on Friday said though the incident may have appeared serious, it was "not a big deal", and a Myanmar defence attache had apologised.
"What is most important is we have enough capacity to defend our sovereignty," Prayuth told reporters.
A spokesperson for Myanmar's junta did not immediately respond to a request for comment and made no mention of the incident in his early remarks on Thai relations at a regular news briefing on Friday.
Myanmar's military has stepped up operations against ethnic minority armies since a coup last year and is encountering resistance on multiple fronts, from old enemies to newly formed militia groups allied with the ousted government.
Activists and aid groups have condemned the junta's use of artillery and air strikes in civilian areas. The United Nations humanitarian agency this week estimated nearly 760,000 people have been displaced by conflict across Myanmar since the coup.
A witness in Thailand told Reuters a fighter jet was seen over two villages about 5 km (3.11 miles) from the border, triggering panic among residents, with one school sending its students to a bomb shelter.
Thai authorities said close to 300 people have fled an intensification of military operations in Myanmar's Karen state in the past few days.