U.S. Defense Secretary Chuck Hagel announced on Friday that Pentagon will spent $1 billion to increase ballistic missile interceptors in California and Alaska to 44 from 30 by 2017. The move is to counter the growing reach of North Korea’s weapons, a decision accelerated by the rogue nation’s recent nuclear strike threats.

The officials said the announcement was intended not merely to present a credible deterrence to the North’s limited intercontinental ballistic missile arsenal, according to New York Times. They said is also meant to show South Korea and Japan that the United States is willing to commit resources to deterring the North.

At the Pentagon news conference, Hagel cited North Korea’s third test of nuclear weapons technology last month, the successful test of a long-range missile that sent a satellite into space, and the discovery that a new generation of mobile missiles appeared closer to development.

“We will strengthen our homeland defense, maintain our commitments to our allies and partners, and make clear to the world that the United States stands firm against aggression,” he said.