Doctors and nurses who treated injured anti-government protesters during the unrest in Bahrain went on trial in a security court on Monday accused of participating in efforts to overthrow the monarchy.

The prosecution of 47 health professionals is a sign that Bahrain's rulers will not end their relentless pursuit of the opposition despite officially lifting emergency rule last week.

The doctors and nurses were charged during a closed hearing in a security court authorised under emergency rule imposed in mid-March. Charges include participating in efforts to topple Bahrain's Sunni monarchy, taking part in illegal rallies, harming the public by spreading false news, denying medical attention to several Sunni patients, assault, embezzlement and possession of weapons.

Selected family members were allowed to attend Monday's arraignment. Amid tight security, relatives were given 30 minutes to talk to the defendants after proceedings were adjourned to give lawyers more time to prepare for their clients' defence. Another hearing in the case is set for 13 June.

During the unrest, medical staff in Bahrain repeatedly said they were under professional duty to treat all casualties and strongly rejected claims by authorities that helping anti-government protesters was akin to supporting their cause.

Most of the accused worked at the Salmaniya medical complex in the capital, Manama, which was taken over by Bahrain's military after martial law was imposed on 15 March. The government said the complex was used to stage protests against the 200-year rule of the Al Khalifa family and conduct illegal political activities.

The doctors and patients in Salmaniya said soldiers and police conducted interrogations and detentions inside the complex and many injured protesters did not seek treatment there for fear of being arrested.

At least 31 people have died since the protests began in mid-February. The US, which has a naval base in the country, has called on Bahrain's leaders to try to meet some of the protest movement's demands.

Hundreds of protesters, opposition leaders, human rights activists, athletes and Shia professionals have been detained and two protesters have been sentenced to death.

Emergency rule was lifted last Wednesday and protesters marched on the capital's Pearl Roundabout on Friday. They were met with teargas and rubber bullets fired by police.

• This article was amended on 9 June 2011. The original said protesters marched on the capital's Pearl Square. This has been corrected.