Four U.S. citizens were kidnapped after gunmen opened fire on their vehicle in the northern Mexico border city of Matamoros, the FBI said Sunday. The four entered Matamoros, across from Brownsville, Texas, on Friday. They were traveling in a white minivan with South Carolina license plates, according to officials. Editor's note: A previous version of this story said the license plates were from North Carolina. Mexican President Andrés Manuel López Obrador said Monday that the four Americans were going to buy medicine and ended up in the crossfire between two armed groups, without offering details. For more: https://bit.ly/3L14F31 ►Subscribe: https://on.wtsp.com/youtube ►Website: https://www.wtsp.com/ ►Facebook: https://facebook.com/10TampaBay ►Twitter: https://twitter.com/10TampaBay