Lao police on Saturday released 25 Thais who stirred up violence during a football match in Vientiane on Friday night, the Thai embassy said.
The embassy said Lao authorities contacted Thai diplomats in Vientiane to arrange for the hooligans to be sent home and they were freed from detention.
The War Elephants played Vietnam in the Asean Football Federation Under-19 final at the National Sports Complex Stadium in the Lao capital. The Thai side thrashed Vietnam 6-0 to take the Asean championship.
Trouble erupted after the Thai team scored its second goal 11 minutes into the second half as a group of fans set off fireworks, prompting Lao police to confront the visitors, Siam Sport reported on its website.
A police officer fired a bullet into the air to quell the disturbance and the fans were removed from the stadium to be detained, it added.
Lao authorities seized the passports and ID cards of the fans calling themselves "Ultras Thailand", according to Matichon Online.
The Thai embassy issued a statement on Saturday to apologise to Laos for the "rude action" of the fans.
"The embassy regrets and apologises to officials and all Lao people for what happened," the statement said.
The Football Association of Thailand plans to ban the hooligans, probably for life, after reviewing the case.
"The association will look into this matter. If they are the same group who have made trouble before, we could ban them from all games for the rest of their lives," Pol Lt Col Chaisup Tharatritpiem, an association member, told Matichon Online.