Chilling footage shows a group of smugglers armed with machine guns escorting a woman and her young son across the US-Mexico border.

Four to five masked men clad in full tactical gear and holding AK-47 assault rifles can be seen guiding the Guatemalan woman and her 8-year-old child under a border barrier and into Arizona Saturday night, government surveillance footage shows.

When camera operators noticed the breach, about a dozen US Border Patrol agents responded and took the woman and her son into custody — but the armed men had already turned back across the border, according to Fox News.

A border patrol official called the incident “highly unusual and highly concerning” for the agency, the outlet reported.

“These armed individuals along the border represent an escalation of tactics,” the official said. “This is not mom and dad and kids deciding to head to the border. This is a no kidding, orchestrated effort to bring individuals to the US. It is not just the numbers. It’s who is running this enterprise.”