The trial of a prominent human rights activist was postponed Sunday for 10 days at the request of the defense who asked for a former European ambassador to stand as a witness, a human rights group and a lawyer said. Anwar al-Bunni, a lawyer and member of the Human Rights Association in Syria, was arrested in May along with nine others, including a prominent Syrian writer and democracy campaigner, Michel Kilo, after signing a petition for Syria to improve strained relations with Lebanon, exchange diplomats and demarcate borders between the two neighbors. The Defense asked Sunday that the former Ambassador of the European Community Mission in Damascus, Frank Heske, testify as a witness in the case, defense lawyer Khalil Maatouk said in a statement. Heske does not live in Damascus and it was not immediately clear if he would testify. There was no immediate word from the Syrian authorities, which rarely comments on the detention and prosecution of suspects wanted in political cases.