Search Underway for 4 Americans Kidnapped in Mexico

There’s a desperate search underway for four Americans kidnapped in Mexico.

Chilling video posted to social media shows them being forced at gunpoint by men with bulletproof vests into the back of a pick-up truck in broad daylight.

It happened shortly after the U.S. citizens crossed from Brownsville into Matamoros, Mexico.

In the video, one woman is alive and sitting up. The others appear either dead or wounded.

The FBI says the Americans entered Matamoros on Friday in a white minivan with North Carolina license plates before armed gunmen opened fire and abducted them.

Photos from the scene appear to show a white minivan with the driver’s side window shot out and multiple people lying in the street surrounded by a rifle-toting gunman.

“We are closely following the assault and kidnapping of four U.S. citizens in Matamoros, Mexico. These sorts of attacks are unacceptable,” said White House Press Secretary Karine Jean-Pierre.

Authorities say an innocent Mexican citizen was killed in the incident.

A law enforcement official tells NBC News the Americans did not cross the border for any criminal purpose, and that this appears to be a case of mistaken identity.

Monday, Mexico’s president said the citizens entered the country to buy medicine, though a law enforcement source with knowledge of the matter tells NBC News it was for cosmetic surgery.

For years, a night out in Matamoros was part of the “two-nation vacation” for spring breakers flocking to South Padre Island.

But violence there has escalated over the past decade with the takeover of the Gulf drug cartel.

Friday’s shootout prompted the U.S. Consulate to issue another security alert in addition to the State Department’s “do not travel” warning for the area.

The FBI is offering a $50,000 reward for the Americans’ safe return.