MEXICO CITY (Reuters) - Reports that a woman in northern Mexico is pregnant with nine babies are a hoax, health authorities said on Friday.

Mexico's main broadcaster Televisa and top daily newspapers ran stories about a woman expecting nonuplets late on Thursday after she provided welfare officials with supposed evidence of the multiple pregnancy, including an ultrasound video, said a spokesman for the health ministry of Coahuila state.

Following the news, local health authorities offered assistance to the woman, who was identified as 32-year-old Karla Perez from Villa Arteaga, east of the state capital Saltillo.

Reports said Perez had conceived the babies after receiving fertility treatment, but tests carried out by doctors on Friday revealed she was not even pregnant. It was not clear why the mother of three had made the claims, the spokesman added.