A mass trial of doctors and nurses accused of backing efforts to bring down the Government of Bahrain was postponed yesterday amid claims of torture and brutality on the part of the country's security forces.

Thirty-four medical staff attended court out of 47 - 23 doctors and 24 nurses - who were charged with anti-state activities last month. It was not immediately clear why some were missing.

The doctors and nurses face allegations ranging from possessing weapons to harming the public by spreading false news and seeking to overthrow the ruling system in the strategic Gulf kingdom, which is home to the US Navy's 5th Fleet.

But the trial was adjourned for a second time to next Tuesday after the chief judge at the special security tribunal accepted a request that the detainees should be medically examined to establish if they had been tortured.

Lawyers for Bassim Dhaif, a consultant orthopaedic surgeon, said he had been forced to stand for two weeks, resulting in loss of sensation, swelling and discoloration of his feet and legs. Abdulla Al-Durazi, a trainee surgeon, had suffered a broken nose since the last court hearing and needed specialist care.

Some had signed false confessions under threat, and lawyers demanded they be re-investigated. When the accused attempted to describe the torture to the court, the judge ordered them to be silent and had one doctor, Zahra Al-Sammak, a consultant anaesthetist, escorted from the court.

The detainees say their only "crime" was to treat injured protesters.

Demonstrations led by Shia Muslims, who comprise 70 per cent of the population, started in February in protest at the discrimination they say they suffer at the hands of Bahrain's Sunni rulers.

But the protests were crushed by the state, and a campaign of intimidation began against the doctors and nurses. Wounded protesters were afraid to seek treatment and ambulances were blocked from going out to retrieve the injured, they said.

On Monday, the court sentenced a woman, 20, to a year in prison for reciting poetry critical of Bahrain's King.