A reporter for Al Jazeera has been missing in Syria since 29 April, the network said in a statement on its website, demanding immediate information on her whereabouts. The Syrian authorities have confirmed that Dorothy Parvaz is in their custody, news reports said.

Parvaz, a 39-year-old journalist working with Al Jazeera’s English-language channel, has not been in touch since she landed in Damascus on a Qatar Airways flight from Doha, Al-Jazeera reported. Parvaz, a U.S./Canadian/Iranian national, has been operating from Doha since August 2010 for the network.

An Al Jazeera spokesman was reported as saying: “We are concerned for Dorothy’s safety and wellbeing. We are requesting full cooperation from the Syrian authorities to determine how she was processed at the airport and what her current location is. We want her returned to us immediately.”

Todd Barker, Parvaz’s fiancé, told The New York Times that the American, Canadian and Iranian embassies in Damascus had all sought information from the Syrian government. Parvaz did not have the time to get a Syrian visa and was probably traveling on her Iranian passport, he added.

IPI Press Freedom Manager Anthony Mills said: “We urge the Syrian authorities to be more transparent about the whereabouts of Dorothy Parvaz, and the circumstances of her detention. If she is being held because of her work as a journalist she should be released immediately.”

Parvaz’s disappearance is the latest in a series of attacks on media personnel as protests continue against President Bashar al-Assad. Two Reuters reporters, Suleiman Al-Khalidi and Khaled al-Hariri, temporarily went missing when the protests started, before being freed, while the accreditation of another journalist was withdrawn by the government for “unprofessional and false” coverage of events.