Mexican and US authorities are working together to identify him four Americans who accepted armed attack in the north Mexico and they were kidnapped shortly after they crossed the borders of the two countries.

The four Americans, whose identities have not been released, were riding in a white minivan with North Carolina plates when they passed through Matamoros, Tamaulipas State, Mexico, last Friday, the US embassy said, appealing for help from citizens to identify the kidnappers.

The gunmen allegedly shot the occupants of the minivan and then put them in another vehicle and fled the area.

A Mexican official told Reuters that the victims of the kidnapping were three men and one woman.

The US ambassador to Mexico, Ken Salazar, said an “innocent Mexican” was killed during the incident.

Mexican President Andres Manuel Lopez Obrador said today that the Americans crossed the border to buy medicine and that the Ministry of Public Security was working with the FBI to find the hostages.

The FBI offered a $50,000 reward for the return of the four and the arrest of those involved in the case.

The White House announced that President Joe Biden has been informed of the “unacceptable” kidnapping of the four Americans. Spokeswoman Karin Jean-Pierre said Washington is ready to provide appropriate consular assistance and confirmed that US law enforcement is in contact with their Mexican counterparts.