One of the men accused of murdering Fusilier Lee Rigby outside Woolwich Barracks has been attacked in prison.
Michael Adebolajo, 28, of Romford in Essex, was set upon at HMP Belmarsh in south east London on Wednesday.
The Prison Service would not comment on reports that he lost two teeth in the incident and had been "targeted" by prison officers.
A spokeswoman said: "The police are investing an incident that took place at HMP Belmarsh on July 17.
"It would be inappropriate to comment while the investigation was ongoing."
Adebolajo is accused of hacking Fusilier Rigby to death together with Michael Adebowale, 22, near Woolwich Barracks in south east London on May 22.
The pair are expected to stand trial on November 18.
Following the attack, thousands of people paid their respects at the scene of Fusilier Rigby's death.
But despite pleas from police and the soldier's family for his death not to be used for political gain, there have also been several clashes between rival protesters.