WASHINGTON (AP) -- The Air Force says its test launch of an intercontinental ballistic missile, which Defense Secretary Chuck Hagel had postponed in April because of tensions with North Korea, is now scheduled to happen on Tuesday.

The unarmed Minuteman 3 missile is to be launched from Vandenberg Air Force Base, Calif., and travel 4,190 miles to the Kwajalein Atoll in the Pacific Ocean. It is one in a series of periodic launches to ensure that the ICBM force is reliable.

The U.S. has 450 nuclear-armed Minuteman 3 missiles ready for combat use, if directed by the president. They are in underground silos in five states.

In April the Pentagon said Hagel postponed the test launch from Vandenberg because of concern that it could be misinterpreted and exacerbate the Korean crisis.