PENITAS, Texas (KVEO) —  Three women have been missing in Mexico since last month after crossing the Anzalduas International Bridge in Mission, Texas, U.S. authorities said Friday.

The FBI said it is aware that two sisters – Marina Perez Rios, 48, and Maritza Trinidad Perez Rios, 47 – from Peñitas, a small border city in Texas near McAllen, and their friend – Dora Alicia Cervantes Saenz, 53 – have gone missing. Peñitas Police Chief Roel Bermea said their families have been in touch with Mexican authorities, who are investigating their disappearance.

The family reported the women missing on Monday, Feb. 27, to the Peñitas Police Department. Three days earlier, the women had left for Montemorelos, Nuevo Leon, to sell clothes at a flea market, the family told police.

On Tuesday, Feb. 28, Peñitas Police notified the FBI.

The husband of one of the women spoke to her by phone while she was traveling in Mexico, Peñitas Police Chief Roel Bermea said, but grew concerned when he couldn’t reach her afterward.

Bermea told the Associated Press the women were traveling in a green mid-1990s Chevy Silverado to Montemorelos, a roughly three-hour drive from the border. Officials in the U.S. and Mexico haven’t said much about their pursuit of Maritza, Marina, and Dora.

Nexstar’s KVEO contacted the FBI, who gave the following statement regarding the missing women: “The FBI is aware of this matter; however, no information is being released at this time.”

Amid this investigation, and the recent kidnapping of four Americans in Matamoros, Mexico, the Texas Department of Public Safety issued a warning urging Texans to avoid travel to Mexico for spring break because of ongoing violence.

The Associated Press contributed to this report.