The defense secretary took issue with multiple questions, at times talking over Senators at the hearing.
The scope and timing of a potential Russian counterattack was still unclear as of Wednesday afternoon, the German defense minister said.
The Air Force's top uniformed leader said that planners need to consider vulnerabilities at military sites once thought untouchable by enemy forces.
Dubbed "The Incredibly Stupid One" by his captors, 20-year-old sailor Douglas Hegdahl was quietly building intelligence.
