Thailand's King Bhumibol Adulyadej has gone back into hospital, only a few weeks after being discharged, the BBC reported.

A statement from the palace on Sunday said he was undergoing tests at the Siriraj Hospital in Bangkok but did not say when he was likely to return to his home in the coastal city of Hua Hin.

The 87-year-old monarch has been in poor health for some years.

He has rarely been seen in public since he went into hospital last October to have his gall bladder removed.