Latest update from NYT

> According to a social media post by the Secretary of Transportation, Sean Duffy, Mexican cartel drones breached U.S. airspace, prompting temporary closure of airspace over El Paso. The Defense Department took action to disable the drones, Mr. Duffy said. Another person familiar with the situation had described the cause of the shutdown as a test of anti-drone technology. It is unclear if the brief airport closure was directly related to the presence of drones or how the technology was deployed.

It does not seem implausible or unreasonable to me that an anti-drone system would trigger airspace restrictions when activated. Whether system activation is intended to put out a 10 days block is probably a different issue, but probably related to SOP for an event of unknown duration.