The first Bosnian Serb convicted of genocide for his role in the 1995 massacre at Srebrenica has been attacked in a British prison, sources said.
Radislav Krstic, 62, was taken to hospital after being attacked by three inmates at the high-security Wakefield Prison.
The former general is serving his 35-year sentence for aiding and abetting genocide after being transferred to the prison from The Hague in 2004.
Krstic's forces helped organise the slaughter of thousands of men and teenage boys in Europe's worst civilian massacre since the Second World War.
A West Yorkshire Police spokesman said: "Police were called to Wakefield Prison at lunch time today to an allegation of assault."
He said the inmate was taken to hospital with "serious injuries".
"West Yorkshire Police are currently investigating the matter," he said. "Inquiries are at an early stage."
A Ministry of Justice spokesman confirmed a prisoner was assaulted by three inmates at 11.30am.
Sources said Krstic was in a serious condition when he was taken to hospital but was returned to jail later.
They said Krstic sustained cuts to his neck.
