Mexican authorities have issued an “urgent” Amber Alert for a missing American teenager after she was last spotted on Sinaloa drug cartel turf nearly three weeks ago, according to reports.

Shelbie Lynn Dwyer, 17, was last seen in a stationery store and internet cafe on March 31 in Salvador Alvarado in the Mexican state of Sinaloa, one of the regions plagued by drug cartel violence, the Mexican news outlet El Milenio reported.