The US Customs and Border Protection agency officers shot down several balloons with a top-secret laser weapon, mistaking them for drug traffickers’ drones, and this led to the closure of airspace over El Paso, Texas, and much of southern part of the US state of New Mexico, The Wall Street Journal reports.

It turned out that the experimental laser system used by the military could pose a serious threat to commercial aviation.

The incident, which plunged El Paso into chaos for several hours and caused outrage in Washington, in particular at the Pentagon, officials rushed to find out what had happened and who was to blame.

According to lawmakers and experts familiar with the situation, this conflict is due to a misunderstanding between the Pentagon, the US Federal Aviation Administration, and the US Department of Homeland Security about who should neutralize the threat of drones over major US airports and military bases and use laser weapons for this purpose.