A Vietnamese man held in a solitary cell at an immigration detention center in Japan committed suicide, a Vietnamese community leader said, raising fresh questions over conditions in the country's detention facilities.

Nguyen The Hung killed himself on Saturday at the East Japan Immigration Center in Ibaraki Prefecture, said Tam Tri Thich, a Buddhist nun who said she received the information from the Vietnamese Embassy in Tokyo.

The Vietnamese Embassy could not immediately be reached for comment. Reuters was not able to independently verify the man's identity.