Dozens of doctors and nurses who treated injured anti-government protesters during the months of unrest in Bahrain went on trial in a security court on Monday on allegations they participated in efforts to overthrow the Gulf kingdom's monarchy.

The 47 health professionals include 23 doctors and 24 nurses detained since March, when martial law was imposed to quell a wave of Shiite-led demonstrations for greater freedoms in the island nation that hosts the U.S. Navy's 5th Fleet.

Emergency rule was lifted on Wednesday and protesters again marched on the capital's iconic Pearl Square on Friday, facing tear gas and rubber bullets from Bahraini police.

The doctors and nurses were arraigned on Monday during a closed hearing in a security court authorized under emergency rule. The court has military prosecutors and military and civilian judges.

The health professionals were charged with participating in efforts to topple Bahrain's Sunni monarchy and taking part in illegal rallies. Other charges against the doctors and nurses, who mostly treated injured protesters in the state-run Salmaniya Medical Complex in the capital Manama, include harming the public by spreading false news and denying medical attention.

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

Bahrain's military took over the Salmaniya hospital after martial law was imposed March 15, and doctors and patients said soldiers and police had conducted interrogations and detentions inside the complex.

International rights groups have criticized Bahrain's campaign against medical professionals, saying that authorities are deliberately targeting doctors and nurses who treated hundreds of injured demonstrators at the Salmaniya hospital during weeks of demonstrations against the 200-year rule of the Al Khalifa family.

At least 31 people have died since the protests, inspired by revolts around the Middle East, began in mid February. Among the dead are also four opposition supporters who died in custody. The U.S. has called on Bahrain's leaders to try to meet at least some of the protest movement's demands.

Hundreds of protesters, opposition leaders, human rights activists, athletes and Shiite professionals have been detained during two and half months of a harsh crackdown. Two protesters were sentenced to death.