The teenage girl and her younger brother were last spotted Friday leaving a home together in Real de San Felipe, a neighborhood in the municipality of García, Nuevo León state, Mexico.
"Because of the circumstances of their disappearance, age and the time passes, the missing minors could find themselves in imminent danger," the alert said in Spanish.
BODIES OF 2 AMERICANS KILLED IN MEXICO RETURNED TO US
Hugo Yarset Monfort Luna, 9, and his 16-year-old sister, Aranza Yosemiti Monfort Luna have been missing since Friday. (Fiscalía Nuevo León)
It’s unclear whether the children lived in Mexico or the United States.
"We are aware of reports of two missing U.S. citizens in Mexico," a U.S. State Department spokesperson told Fox News Digital Tuesday. "Due to privacy considerations, we have no further comment."
The boy is described as 3-foot-6, with dark, straight brown hair and dark brown eyes and is missing a tooth on the lower jaw on the right side. The teen girl, described as 5-foot-2 with straight dark brown hair and a brown spot over her right cheek, was last seen wearing black pants, a pink shirt, a long gray sweater with blue sneakers, according to the local prosecutor’s office. She also reportedly had a black sweater tied around her waist and was carrying a brown handbag.
AMERICAN CITIZEN 'KIDNAPPED FROM HER RESIDENCE' IN MEXICO, FBI SAYS
Fox News Digital also reached out to the FBI Tuesday but did not hear back before publication.
The State Department's travel advisory for Mexico warns, "Violent crime – such as homicide, kidnapping, carjacking, and robbery – is widespread and common in Mexico. The U.S. government has limited ability to provide emergency services to U.S. citizens in many areas of Mexico, as travel by U.S. government employees to certain areas is prohibited or restricted."
Americans are warned to exercise "increased caution" when traveling to Nuevo Leon due to crime and kidnapping.
Friends of Zindell Jones mourn his loss at a prayer vigil at Word of God Outreach Ministries in Scranton, South Carolina, on March 8, 2023. He was one of four Americans kidnapped while crossing into Mexico earlier this month. (Mark Darrough for Fox News Digital)
The children disappeared exactly two weeks after four Americans from South Carolina were fired upon and kidnapped while driving a minivan across the border from Brownsville, Texas, to the city of Matamoros in the northeastern Mexican state of Tamaulipas on March 3. Mexican authorities later rescued two of them, Latavia McGee and Eric Williams, alive and found the bodies of the two others, Zindell Brown and Shaeed Woodard, dead at a wooden shack on the outskirts of Matamoros.
Maria del Carmen Lopez is a U.S. citizen who "was kidnapped from her residence in Pueblo Nuevo, Colima, Mexico, on Feb. 9, 2023," the FBI says. (FBI)
In a separate case, the FBI’s Los Angeles Field Office on Friday said they were asking for the public's assistance in locating Maria del Carmen Lopez, a U.S. citizen and California mother of seven, who was kidnapped from her residence in Pueblo Nuevo, Colima, Mexico, on Feb. 9.