Egyptian police have broken up a pro-reform protest at the Judges' Syndicate in Cairo, beating one senior judge and detaining 15 protesters.

Fifty judges have been holding a sit-in at their headquarters to protest against the prosecution of two of their colleagues by the government.

Police moved against demonstrators overnight and struck a judge who came out to defend them, witnesses said.

Judge Mahmoud Hamza was taken to hospital but was not seriously hurt.