BOSTON -- A military transport plane made an emergency landing in New Hampshire on Wednesday after a crack was spotted in a window.

New Hampshire National Guard said a KC-135 landed at Pease Air National Guard base Wednesday. The crack, described as small, was found in one of the cockpit windows.

As a precaution, the military aircraft circled the air field to burn off fuel before making the landing.

Four crewmembers were onboard and there were no reports of injuries.

It was not immediately clear what caused the window to crack.