Sirhan Sirhan, imprisoned for more than 50 years for the 1968 assassination of Senator Robert F Kennedy, has been hospitalised after being stabbed by a fellow inmate in a United States prison.

Key points: Corrections officials said the alleged attacker had been identified and an investigation is underway

Corrections officials said the alleged attacker had been identified and an investigation is underway Sirhan fatally shot Robert F Kennedy in 1968 shortly after the US senator's victory speech

Sirhan fatally shot Robert F Kennedy in 1968 shortly after the US senator's victory speech He requested to be moved to the general prison population several years ago

A statement from the state Department of Corrections and Rehabilitation said the stabbing occurred on Friday afternoon (local time) at the Richard J Donovan Correctional Facility near San Diego.

"Officers responded quickly, and found an inmate with stab wound injuries. He was transported to an outside hospital for medical care, and is currently in stable condition," the statement said.

The statement did not name Sirhan, but a government source with direct knowledge confirmed to the Associated Press that he was the victim.

The source spoke under condition of anonymity, citing prison privacy regulations.

The stabbing was first reported by TMZ.

Loading...

Corrections officials reported that the alleged attacker had been identified and segregated from the rest of the prison population pending an investigation.

Sirhan, 75, was convicted of shooting Kennedy shortly after midnight on June 5, 1968, immediately after the New York senator had declared victory in the previous day's California Democratic presidential primary.

Kennedy had just finished delivering his victory speech to cheering supporters at Los Angeles' Ambassador Hotel when he decided to walk through the hotel kitchen.

He had stopped to shake hands with a busboy who had delivered food to his room the day before when he was shot in the head. He died the next day.

Sirhan has been denied parole several times for the murder of Robert F Kennedy (left). ( JFK Presidential Library: Abbie Rowe )

Sirhan was originally sentenced to death, but when California briefly outlawed capital punishment, his sentence was reduced to life in prison.

He has been denied parole several times.

Five bystanders were wounded during the shooting. In the chaos, Los Angeles Rams football great Rosey Grier, Olympic champion Rafer Johnson and others wrestled the murder weapon away.

Over the years, Sirhan has claimed to have no recollection of the shooting or his initial confession.

As a high-profile prisoner, Sirhan had once been kept in a protective housing unit at Corcoran State Prison in Northern California.

After he told authorities several years ago that he would prefer being housed with the general prison population, he was moved to the Richard J Donovan Correctional Facility.

AP