MINOT, N.D. (AP) — The number of Minuteman III intercontinental ballistic missiles in northern North Dakota will shrink from 150 to 133 by next February under a nuclear arms reduction treaty with Russia.

The Minot Daily News reports the treaty was signed in April 2010 by former President Barack Obama and former Russian President Dmitry Medvedev. It went into effect Feb. 5, 2011, and is expected to last until 2021. Under the treaty, both nations are to comply with the reduction of nuclear arms by February 2018.

An Air Force Global Strike Command spokesman says the Minot Air Force Base will still maintain 150 missile silos. Seventeen of them will be empty but usable

Minot's base is the only one with dual nuclear-capable wings, the 5th Bomb Wing and the 91st Missile Wing.