The US plans to beef up its missile defenses in response to growing threats from North Korea.
More from GlobalPost: North Korea launches missiles in East Sea
According to Hagel, up to 14 additional missile interceptors will be deployed at Fort Greeley in Alaska and a radar tracking station deployed in Japan.
Two other potential missile locations weren't disclosed, but would be somewhere on the East Coast, Fox News reported.
The system would be in place by 2017 at a cost just under $1 billion, Hagel said.
Currently, there are 26 ground-based interceptors built by Orbital Sciences Corp. in Alaska and four in California, according to Bloomberg.
More from GlobalPost: UN approves sanctions after North Korea threatens nuclear strike against US
While there's no evidence yet that North Korea is targeting the US with nuclear missiles, the country has been ratcheting up threats and war rhetoric almost daily in recent weeks.
North Korean officials recently threatened to reduce Seoul to a "sea of fire" and stage pre-emptive nuclear attacks on Washington, The Associated Press reported.
North Korea also fired short-range missiles into the East Sea today and conducted live-artillery exercises in the West Sea earlier this week following a nuclear test in February.
The UN Security Council imposed new sanctions against North Korea in response, heightening international tensions.