FBI reports 4 American citizens abducted and abused in Matamoros, Mexico.

(CNN) ⸻ Four US citizens were assaulted and kidnapped after crossing the border into northeastern Mexico on Friday, according to the FBI. The US citizens were driving a white minivan with North Carolina license plates. The FBI is seeking the public's help in locating the Americans and identifying those responsible for the kidnapping. The US State Department has issued a "Level 4: Do Not Travel" advisory for US citizens thinking of going to Tamaulipas, citing crime and kidnapping. The FBI said it is cooperating with other federal partners and Mexican law enforcement agencies to investigate the kidnapping. Anyone with information related to the incident is encouraged to call the FBI San Antonio Division or submit a tip online.