Dorothy Parvaz, who holds U.S., Canadian, and Iranian citizenship, disappeared after she flew to Damascus from Qatar on April 29.
Syria said earlier this month that Parvaz was put on a plane to Tehran on May 1, escorted by the Iranian consul in Damascus, because she had been carrying an expired Iranian passport.
Iranian authorities have not confirmed Parvaz is in Iran, though Foreign Ministry spokesman Ramin Mehmanparast told a briefing on May 17 that the ministry is "following" the case.
Parvaz's father Firouz told Radio Farda one day earlier he had not heard from his daughter since April 28.
He said he has contacted the Iranian Embassy in Canada, where he now lives, to solicit information about his daughter.
Firouz Parvaz said he hopes "the Iranian authorities treat Dorothy with compassion and let her call us to relieve us from anxiety." He added that his daughter, who was born in Iran, has visited that country only once in the past 30 years, for two weeks in 2006.
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