SAN DIEGO (Border Report) — During a routine patrol along the San Ysidro Mountains last month, border agents encountered four men who were heavily armed with AR-15-style rifles and loaded high-capacity magazines.

The incident happened in the afternoon of Oct. 25 late just north of the border barrier southeast of downtown San Diego.

Border Patrol officials said when the men noticed the U.S. agents, they dropped their weapons and fled south into Mexico.

Agents then notified their Mexican counterparts who responded to assist.

The San Diego Sector Border Patrol Tactical Unit, also known as BORTAC, was brought in to provide additional security.

These photos provided by the U.S. Border Patrol show weapons and ammunition carried by four suspects who came across the border and wandered into the San Ysidro Mountains southeast of downtown San Diego. (Courtesy: Border Patrol)

Once the scene was deemed safe, agents searched the area and recovered four AR-15-style rifles and 17 loaded AR-15 magazines.

In a statement, Border Patrol said the weapons, ammunition, and other evidentiary items were seized and transported for processing.

As of now, no arrests have been made in connection with the incident.

“This type of dangerous activity must not be tolerated,” said San Diego Chief Patrol Agent Aaron M. Heitke. “When events like this occur, we think of our fallen Border Patrol Agents Bryan Terry, Robert Rosas, and others who have paid the ultimate sacrifice in service to this nation.

Heitke also said this type of activity has taken place before with migrants being targeted.

“We think of the migrant victims of armed extortion, robbery or worse, and we think of the dangers to outdoor enthusiasts who frequent the area,” he said.