(CNN) -- Defense Secretary Chuck Hagel is expected to announce Friday that the Pentagon will enhance the nation's ability to defend itself from any nuclear attack by North Korea, a U.S. defense official told CNN.
Hagel will announce that the United States will deploy up to 14 additional ground-based missile interceptors, according to the official.
Part of the move would involve reopening a missile field at Fort Greely, Alaska, and some of the interceptors would be based in California.
It will take two years for all of the systems to come online.
The move comes after North Korea recently threatened a pre-emptive nuclear attack on South Korea and the United States in response to stepped-up U.N. Security Council sanctions over its latest nuclear test.
North Korea also said last week it was nullifying the joint declaration on the de-nuclearization of the Korean Peninsula.
One of the country's top generals, according to published reports, claims Pyongyang has nuclear-tipped intercontinental ballistic missiles that are ready to be fired.
Military and White House officials have said the United States can defend against any such threat, and President Barack Obama said in an interview with ABC News this week that he does not think North Korea can make good on the threat.
"They probably can't but we don't like margin of error," Obama said.
In 2011, the Pentagon mothballed Missile Field 1 in Alaska, acting on direction from the Obama administration. Instead of permanently decommissioning it, the Defense Missile Agency placed it in a non-operational state.
Pentagon officials testified at a budget hearing at the time that hardening and reactivating the six silos in Missile Field 1 would take two years and cost approximately $200 million. Pentagon officials testified then that "there are no current threats dictating the need, nor plans to reactivate MF-1 in the future."
Republican congressional sources told CNN that they argued against the move.
"North Korea was doing all sorts of things we couldn't talk about publicly back then," said one GOP congressional official who is privy to intelligence briefings. "The intelligence did not change. This is right where we expected North Korea to be. It takes about two years to order and take delivery of a new interceptor. That's why you have to be ahead of the threat."
In his State of the Union address last month, Obama said the United States would "stand by our allies, strengthen our own missile defense and lead the world in taking firm action in response to these threats."
Last week, Undersecretary of Defense for Policy James Miller told the Atlantic Council that "North Korea's shrill public pronouncements underscore the need for the U.S. to continue to take prudent steps to defeat any future North Korean" intercontinental ballistic missile.