The humanitarian group Doctors Without Borders says it is ending its operations in Thailand after 35 years.
The group's chief in Thailand, Denis Penoy, said Thursday it is halting its activities because it could not reach agreement with the government on conditions under which it could provide medical care to illegal migrants.
Most of Thailand's estimated 2 million unregistered migrants come from Myanmar, and their status prevents them from receiving proper health care.
Government spokeswoman Thitima Chaisaeng said she could not immediately comment because she was not familiar with the details of the group's decision.
The group's first activity in Thailand was helping Cambodian refugees fleeing the Khmer Rouge in 1976.