The FBI is currently searching for four American citizens who were reportedly abducted and attacked after crossing the northeastern Mexican border on Friday.

Upon entering the border city of Matamoros, the individuals were met with gunfire from unidentified assailants. The FBI, based in San Antonio, has not disclosed the identities of the victims.

“All four Americans were placed in a vehicle and taken from the scene by armed men,” the release said.

According to the FBI, four US citizens were kidnapped and assaulted after crossing the northeastern border into Mexico on Friday. The FBI has not revealed the identities of the victims but did mention that they were driving a white minivan with North Carolina license plates.

After crossing the border, the Americans were shot at by unknown assailants in the city of Matamoros. The FBI is requesting public assistance in locating the missing Americans and identifying the perpetrators, offering a reward of $50,000 for information leading to their return and the arrest of those responsible.

The FBI is working in collaboration with other federal agencies and Mexican law enforcement to investigate the incident. CNN has reached out to the FBI for more information on the victims and is seeking comments from various Mexican government authorities.

Since the Mexican Drug War began in 2006, Matamoros, a border city in Tamaulipas, Mexico, with a population of over 500,000, has been plagued by violence and organized crime.

According to the Congressional Research Service, the Gulf Cartel, a once-powerful smuggling operation that has since fragmented into small, rival gangs, is based in the city.

On the same day as the purported kidnappings, police advised parents to keep their children at home from school following two shootings in the area.

The State Department has cautioned US citizens against traveling to Tamaulipas, giving it a “Level 4: Do Not Travel” warning due to the high incidence of crime and kidnapping. Criminal groups in Tamaulipas often target public and private transportation, including buses and private vehicles, taking passengers and demanding ransom payments.

Matamoros, located in the Mexican state of Tamaulipas, is a city of over 500,000 people, situated across from Brownsville, Texas. It has been beset by violence and organized crime, especially since the Mexican Drug War began in 2006. The Gulf Cartel, a once-powerful smuggling operation, is based in the city, but it has since fractured into smaller, competing gangs.

The city also recently witnessed two shootings, prompting authorities to warn parents to keep their children at home. Matamoros was also the site of a migrant tent encampment mostly consisting of Venezuelans and Haitians who hoped to cross into the US to seek asylum.

Anyone with information related to the incident is encouraged to call the FBI San Antonio Division or submit a tip online.