Syrian authorities have detained an activist who headed a recently formed group promoting peaceful and democratic change in Syria, a human rights group said Sunday. The Damascus-based Syrian Organization for Human Rights said Fidaa al-Hourani went to the state security's intelligence headquarters Sunday morning in the northern town of Hama after being summoned and has not been seen or heard of since then. "This phenomena of political detentions must stop," SOHR said in a statement made available to The Associated Press. Individuals summoned to state security who do not immediately reappear are generally assumed in Syria to be under arrest. Al-Hourani, 51, a writer, was elected on Dec. 1 president of the newly formed National Council of the Damascus Declaration - a group of pro-democracy activists working for democratic change in Syria. Over the next few days after the group's forming, authorities summoned and detained about 30 of its members. They later released most of them after questioning, except for Akram al-Bunni, a left-wing opposition lawyer who spent 17 years in jail before his release in 2002, who is still in detention. US President George W. Bush on Friday demanded that Syria release all jailed activists and political prisoners. He applauded the formation of the National Council of the Damascus Declaration, which he said reflects "the desires of the majority of Syrian people to live in freedom, democracy and peace." Separately, Syria's State Security Court on Sunday sentenced four people to jail in sentences ranging between four and ten years on charges of inciting ethnic hatred and trying to change the state's system, another human rights group said. The independent National Organization for Human Rights in Syria (NOHR-S) also said in a statement that security forces dispersed a Kurdish sit-in organized by three banned Kurdish parties in front of the court to protest trials of some Kurds and to commemorate the international human rights day. Qurabi said that security forces rounded up scores of protesters, drove them outside Damascus and released them.