Syrian authorities on Friday released Mohamed Saleh, a prominent opposition figure who had been detained in the central city of Homs, according to rights groups, dpa reported.
Saleh was arrested on Thursday following a phone call from someone posing as an Al Jazeera journalist who had requested an interview, said the London-based Syrian Observatory for Human Rights.
Shortly before his detention, Saleh had met with a group of Russian lawmakers during their visit to Homs and had asked them to assist the Syrian opposition.
Saleh has in the past been jailed for 12 years in Syria.