The Air Force says a Missouri-based B2 stealth bomber landed in Colorado Springs after an unspecified emergency, but neither of the pilots was injured.

Officials say first responders from Peterson Air Force Base responded to the plane after it landed at about 4:20 a.m. Tuesday.

The Air Force in a statement did not disclose the nature of the emergency but says it’s under investigation.

At the time of the landing, the aircraft was returning to its home base at Whiteman Air Force Base, Missouri, about 70 miles (113 kilometers) east of Kansas City.

The Air Force statement did not say where the flight began or what the mission was.

The B2 costs about $1 billion, is designed to evade enemy radar and carries a two-person crew.

(AP)