Belgian authorities have detained an elderly man, reportedly aged 99 or 100, on suspicion of killing a fellow resident of the retirement home where he lived, the Belga press agency has said.

No details of the fatal assault which took place on Monday were immediately available, but the Ghent prosecutor's office confirmed in a statement that a resident of the home was in custody.

"A suspect has been arrested. He is a resident of the nursing home," prosecutors said.

Belga reported that the suspect is "99 or 100 years old", making him likely the oldest detainee in Belgium.

The last known case of a murder in a retirement home in Belgium dates back to the 1990s, according to Vincent Fredericq, secretary general of Femarbel, a leading federation of elderly care providers.

"The son of a resident, himself retired, was one day seized by a moment of madness and had killed his mother before trying to commit suicide," he told AFP.

The management of the "Kouterhof" home, in the town of Destelbergen, declined to comment.