A bomb explosion on Tuesday in the compound of Tham Krabok temple, famed as a drug-treatment centre and refuge place for Hmong hilltribe people, injured seven people, police said.
Of the seven Hmong injured by the early-morning blast, one was listed in serious condition at Phra Bhuddabat Hospital, said Police Lieutenant Taweepong Phojiew.
"We suspect that the bomb was the result of a business conflict between rival gangs involved in methamphetamine trafficking," said Taweepong in a telephone interview with Deutsche Presse-Agentur dpa.
There are an estimated 13,000 Hmong refugees currently living in the temple compound.
Tham Krabok, situated in Saraburi Province about 120 kilometres north of Bangkok, is among Thailand's most famous Buddhist temples.
Its former abbot, Chamroon Panchant, who died last year, won international praise for turning the temple into a rehabilitation centre for heroin addicts decades ago.
His more recent effort to transform Tham Krabok into a refuge for thousands of ethnic Hmong hilltribe people fleeing persecution in neighbouring Laos proved more controversial.
Laos frequently accused the abbot of harbouring anti-government elements, whereas Thai authorities have the Hmong community of involvement in drug trafficking.
Abbot Chamroon, a Buddhist monk renowned for his anti-communist sentiments, succeeded for years in resisting government efforts to shut down his refugee centre for the Hmong, who were close allies of the U.S. military during its war against the spread of communism in Indochina.
Thai authorities are investigating whether the Tham Krabok Hmong community was linked to a recent spate of bomb explosions in Vientiane, the capital of Laos.
"We've been secretly investigating whether the Hmong community here was involved in the Vientiane bombings," acknowledged Taweepong. dpa pj jh