The U.S. military is looking into an incident on Saturday in which it lost communications with 50 long-range nuclear-armed missiles based in the northern United States.
The U.S. Air Force's new Global Strike Command lost communications with the missiles for about 45 minutes, and says it immediately dispatched troops to inspect the sites. The check determined there was no damage and no evidence of sabotage.
A spokesman for the command says investigators believe a faulty circuit board at a control center was to blame. The spokesman, Lieutenant Colonel John Thomas, says experts found that the same type of part failed at two other Air Force missile control centers in the late 1990s.
The military has launched two investigations into the incident, but a Pentagon spokesman, Colonel David Lapan, says the Air Force does not see the disruption as significant.
"They have emphasized that there was never a loss of command and control and there was no public safety danger in the incident," said Lapan. "Right now their initial indications are that a computer component in one of the systems may have failed. They are still looking into the exact cause and the circumstances."
Colonel Lapan says the airmen who control some 450 missiles spread across North Dakota, Montana and Wyoming maintained "the capability to carry out their mission" even during the outage. The mission is to launch the missiles at overseas targets in response to a presidential order, which would normally only be done in retaliation for a nuclear attack on the United States.
Under an agreement with Russia, both countries' nuclear-armed missiles are targeted at remote locations in the oceans to help avoid an accidental attack on populated areas.
Two years ago, Defense Secretary Robert Gates fired the top two Air Force officials, saying they had not taken two earlier nuclear control incidents seriously enough. In the first incident, a B-52 bomber flew across the country armed with six nuclear weapons. Not long after that, fuses for nuclear bombs were accidentally shipped to Taiwan instead of other supplies. U.S. officials only found out about the mistake when officials in Taiwan informed them.
Global Strike Command was created, in part, in response to those incidents, as the Air Force's new leaders moved to tighten control on the large U.S. nuclear weapons arsenal. Colonel Lapan says Secretary Gates is monitoring the investigations of the latest incident.