Concern is growing for three human rights defenders being held incommunicado at a military base near Damascus, amid reports they may be facing ongoing torture, Amnesty International said. Hani Zitani, Abd al-Rahman Hamada and Mansour al-Omari are being held in the town of al-Mo’damiya outside the capital, at a base run by the Fourth Armoured Division, under the de facto command of the Syrian president’s brother Maher al-Assad.    Another three of their colleagues detained with them there from March 19 until April 22, were brought before a military court on Sunday, where they alleged that Fourth Armoured Division officials had tortured, including by beatings, all six men during that time. The six men – prisoners of conscience accused of “having an illegal recording with a view to distribute banned publications” – were among 14 men and women arrested in February during a security forces raid on the Syrian Centre for Media and Freedom of Expression in Damascus. “Until now, very little information has been available about the well-being of these human rights defenders held since February’s raid,” said Ann Harrison, Deputy Middle East and North Africa Programme Director at Amnesty International. “Given the seriousness of these new allegations, we urge the authorities to give the detainees immediate access to adequate medical care if needed, and ensure they are protected from torture or other ill-treatment." “As prisoners of conscience arrested and detained solely for their peaceful defence of freedom of expression, the Syrian authorities must release them immediately and unconditionally.” Following their court appearance on Sunday, Bassam Al-Ahmad, Joan Fersso and Ayham Ghazoul were transferred to Damascus Central Prison ('Adra prison), along with five women arrested in the February raid who had been previously released on bail. It is believed that Mazen Darwish, director of the Syrian Centre for Media and Freedom of Expression, and his colleague Hussein Gharir are still being held at Air Force Intelligence, where they were first brought after the February raid. The Syrian Journalists Union on Wednesday claimed that Darwish was suffering from a “worsening health condition” in detention. The Syrian Centre for Media and Freedom of Expression, an organisation that reports on violations against journalists and the press and undue restrictions on freedom of expression, was closed in 2009 by Syrian authorities and was reopened later without government approval. The latest news about the detained human rights activists in Damascus comes as armed clashes and shelling continue in cities across Syria, despite the presence of UN observers deployed as part of a 12 April agreement brokered by the Arab League-UN envoy, Kofi Annan. Earlier this week Annan’s spokesperson said that people who interact with the UN observers apparently risk being “harassed or arrested or even worse, perhaps killed” by Syrian security forces. Amnesty International is particularly concerned by recent reports about violence intensifying in Syrian cities soon after visits by UN observers. The organisation has received the names of 362 individuals reported to have been killed since UN observers began work in Syria on 16 April.  The UN has voted to increase the number of its observers to 300, but this could take weeks to implement without a concerted push to make it happen. “The recent trend of violence surging in Syrian cities directly after UN observers have left underscores the need for a more robust observer mission to be put in place much more quickly,” said Ann Harrison. “The UN must move quickly to establish, as conditions permit, a sustained larger presence of monitors to verify that all aspects of the plan by Kofi Annan are respected.  Unless a fully resourced team is dispatched with urgency, the violence and serious human rights violations can only be expected to continue.”