WASHINGTON -- Responding to a new level of belligerence from North Korea, the United States will place more missile interceptors in Alaska to respond to a nuclear threat that’s advancing faster than anticipated, Defense Secretary Chuck Hagel said Friday.

His announcement comes as North Korea has ratcheted up its rhetoric, threatening to attack the U.S. and taking a more aggressive tone toward South Korea.

Fourteen new ground-based interceptors will be placed mostly in a reopened missile field at Fort Greely, about 100 miles southeast of Fairbanks, and will bring the number of U.S. interceptors in the area to 44. Hagel said the $1 billion program should be ready by 2017.

The defense secretary said it was important to make the move now and “not to take any chances, to stay ahead of the threat and to assure any contingency . . . to make sure we’re not reacting to (North Korea’s) timeline.”

The announcement came at a news briefing by Hagel, who was accompanied by other high-level Pentagon officials. They said the new interceptors would cover all American states and territories.

Besides North Korea’s increasingly warlike posture, development of its missile program has increased as well, defense officials said. Last April, a long-range missile test appeared to be an embarrassing failure. But in December, the communist country appeared to have a successful launch. Last month, it carried out what defense officials said appeared to be a successful underground nuclear test.

Adding to concerns, North Korea recently nullified a 1953 truce with South Korea and threatened a pre-emptive strike against the United States.

Defense officials said there was no evidence to support a North Korean general’s claims this week that the rogue nation has nuclear-tipped intercontinental missiles ready to fire at the United States. But Adm. James Winnefeld Jr., the vice chairman of the Joint Chiefs of Staff, said military officials now thought that the North Korean long-range missile “probably does have the range to hit the United States.”

Sen. James Inhofe, R-Okla., the ranking member of the Senate Armed Services Committee, said in a statement that the move was “a much-needed measure of protection against the North Korean threat.”

But while “a step in the right direction,” Inhofe said, it “does not go far enough to address the threat from Iran.” He said it was time for President Barack Obama to develop interceptor sites on the East Coast, in addition to Alaska.

Stephen Long, an expert on North Korea at the University of Richmond, said Friday’s announcement overstated the North Korean threat. He said North Korean missiles hadn’t been shown to be able to reach U.S. shores and that there was no proof the country’s missile program had miniaturized a warhead necessary for an attack.

“The real chance that North Korea launches anything like a real attack on the United States is pretty much down to zero,” he said.

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