Comoros Communications Minister Abdourahim Said Bakar said earlier reports that the rescued child was five were wrong.
"A doctor from the military hospital aboard one of the rescue boats called the Mitsamiouli hospital to tell them a child had been rescued alive," Halidi Ahmed Abdou, a doctor at a medical centre opened for survivors, told Reuters.
Ibrahim Abdourazak, an official at a crisis centre in Comoros, told Reuters the 14-year-old girl was from a village in the centre of the Indian Ocean archipelago.
Bakar also told Al Jazeera television that a 14-year-old girl had been rescued. He said he thought she was the only survivor.
Hadji Madi Ali, director of the international airport in Moroni, had earlier told national radio the child was five.