4 Americans kidnapped in Mexico by armed gunmen, FBI says

Four U.S. citizens were assaulted and kidnapped by armed gunmen in northeastern Mexico, the FBI said Sunday. 

In a statement released through the U.S. Embassy in Mexico, the FBI said the kidnapping occurred in the city of Matamoros, located in the state of Tamaulipas on the U.S.-Mexico border across from Brownsville, Texas.

The Americans reportedly crossed into Mexico on March 3, driving a white minivan with North Carolina license plates. "Shortly after crossing into Mexico, unidentified gunmen fired upon the passengers in the vehicle," the FBI said, adding that the four Americans "were placed in a vehicle and taken from the scene by armed men."

It is unclear why the four Americans, who have not been identified by the FBI, had crossed into Matamoros. The agency is offering a $50,000 reward for information leading to their return. CBS News reported that a post on Twitter appeared to show the moment of the kidnapping, though the video has not been confirmed by the FBI. 

Matamoros is home to numerous warring factions of the Mexican drug cartels. Shootouts in the city became so bad over the weekend, The Associated Press noted, that "the U.S. Consulate issued an alert about the danger and local authorities warned people to shelter in place." AP added that violence often goes unaccounted for in Matamoros because cartel members take their victims with them. 

The city has long been the base of operations for the Gulf Cartel, described by CNN as "a once-powerful smuggling operation that has splintered into small, competing gangs."

Tamaulipas is one of six Mexican states that the U.S. State Department has issued a 'Do Not Travel' advisory for because of its "organized crime activity — including gun battles, murder, armed robbery, carjacking, kidnapping, forced disappearances, extortion, and sexual assault."