Armed Mexican troops disarmed two United States soldiers while they were on the American side of the border, U.S. defense officials have said.

U.S. Northern Command said in a statement that "five to six Mexican military personnel questioned two U.S. Army soldiers who were conducting border support operations" this month. The U.S. soldiers were in an unmarked Customs and Border Protection [CBP] vehicle near the southwest border near Clint, Texas.

Officials confirmed that the Mexican troops were armed with what seemed to be rifles. They raised their weapons when they saw the two U.S. soldiers, and then took a pistol from one and put it in the CBP vehicle. According to officials talking to CNN, the two Americans obliged "in an attempt to de-escalate a potential volatile situation."

"Throughout the incident, the U.S. soldiers followed all established procedures and protocols," the statement said. The two U.S. troops were on the south side of the security perimeter but north of the Rio Grande and thus were in the U.S., according side American territory, it added.

Pentagon and Department of Homeland Security officials demanded an explanation from the Mexican government. "An inquiry by CBP and DOD [Department of Defense] revealed that the Mexican military members believed that the US Army soldiers were south of the border," the statement said.

"Though they were south of the border fence, U.S. soldiers remained in U.S. territory, north of the actual border."