In a statement on Monday, spokesperson Maj. Gen. Winthai Suvari said the Thai military deployed the aircraft after a deadly clash in Chong Bok area, Nam Yuen district, Ubon Ratchathani province.
Suvari said at least four other soldiers were also injured.
He added that the Thai military is “quickly assisting in the evacuation of civilians in border areas.”
Cambodia also confirmed the attack, according to Al Jazeera.
Cambodian Defense Ministry spokeswoman Marie Socheata told AFP news agency that Thai forces launched attacks on Cambodian troops in the border provinces of Preah Vihear and Odar Meanchey early Monday.
He added that Cambodia had not retaliated.
The attack is the latest flare-up in violence between the neighbors after five days of deadly clashes in July ended with a ceasefire.
At least 48 people were killed in the clashes, an estimated 300,000 people were forced to temporarily evacuate, and the two neighbors exchanged rocket fire and engaged in heavy artillery fire.
The ceasefire that ended hostilities was brokered by Malaysian Prime Minister Anwar Ibrahim and US President Donald Trump, who also witnessed the signing of an expanded peace agreement between the two countries in Kuala Lumpur in October.
MNA