© AFP/File Hassan Ammar

DAMASCUS (AFP) - Four Syrians accused of membership in a secret organisation have denied the charges at the start of their trial in a security court, Syrian human rights groups said on Wednesday.

The trial of Abbas Abbas, Tufiq Omran, Ghassan Hassan and Ahmad al-Nihawi -- all four members of the opposition Communist Labour Party -- opened on Tuesday, four rights watch-dogs said in a joint statement.

"They are accused of membership in a secret organisation whose aim is to change the political and social status of the state," the Syrian Observatory for Human Rights, the Syrian League for the Defence of Human Rights and the National Organisation of Human Rights in Syria said.

The defendants, who have served jail time in the past for their political activities, pleaded not guilty and told the court they ended their involvement in politics.

A new hearing has been set for October 31.

The defendants were arrested in May 2009 in central Syria in a raid on the house of a fifth man, Hassan Zahra, who was subsequently released for health reasons.