The Mexican northern border state of Nuevo Leon has begun a search for two American minors who went missing last week, the state attorney general's office said.
The 16-year-old girl and 9-year-old boy were last seen on March 17, and could be in imminent danger, according to a post by the office on its Facebook account on Monday.
The Nuevo Leon attorney general's office identified the two as Aranza Yosemiti Monfort and her younger brother Hugo Yarset Monfort Luna.
"We are aware of reports of two American citizens missing in Nuevo Leon," a U.S. State Department spokesperson said on Tuesday, declining to give more details due to privacy considerations.
The U.S. Embassy in Mexico did not immediately reply to a request for comment.
Four Americans were kidnapped earlier in March in the border state of Tamaulipas, two of whom were killed in an attack officials have linked to a drug gang.
Five alleged Mexican drug cartel members were arrested over the kidnapping.
(Reporting by Valentine Hilaire, editing by Ed Osmond and Marguerita Choy)