Apr 4, 2013 1:09 PM by NBC News
WASHINGTON, D.C. - North Korea is moving a medium-range missile to a site in the east of the country, a U.S. intelligence official said Thursday as tensions with the nuclear-armed state continued to escalate.
The official declined to say where the Musudan missile was headed, but the North has used a site near the Russian border on the coast for its missile tests in the past.
South Korean Defense Minister Kim Kwan-jin told lawmakers Thursday that the missile had "considerable range" but not enough to hit the U.S. mainland, according to The Associated Press.
The news came hours after North Korea's military warned that it had been authorized to attack the U.S. using "smaller, lighter and diversified" nuclear weapons -- the latest in a string of war cries against America in recent weeks.
"The moment of explosion is approaching fast," the military statement said.
Tensions on the Korean Peninsula rose in December when the North test-fired a rocket and increased again when it tested a nuclear bomb in February.
Russia joined the ranks of countries voicing concern at the escalating crisis, saying the North's disregard for United Nations' restrictions was unacceptable.
The U.S. is sending an advanced anti-ballistic missile system to Guam to protect American military sites, officials said Wednesday.
The Terminal High-Altitude Area Defense system is expected to arrive at the U.S. territory in the Pacific within two weeks.
Defense Secretary Chuck Hagel said the North's provocations were "a real and clear danger and threat" to U.S. interests and stressed that Washington was taking them seriously
"We are doing everything we can ... to defuse that situation on the peninsula," Hagel said after a speech Wednesday at the National Defense University at Fort McNair in Washington, D.C.
"I hope the North will ratchet this very dangerous rhetoric down," he said, adding that there is a pathway to peace but only if Pyongyang decides to be "a responsible member of the world community."
On Thursday, North Korea warned its military had been authorized to carry out "cutting-edge, smaller, lighter and diversified" nuclear strikes to protect itself against the United States.
"The moment of explosion is approaching fast. No one can say a war will break out in Korea or not and whether it will break out today or tomorrow," read the statement of an unnamed military spokesman.
The statement, which was carried by the state-run Korean Central News Agency (KCNA), informed the White House and the Pentagon that "the merciless operation of its revolutionary armed forces in this regard has been finally examined and ratified."
It also made reference to U.S. jet sorties over the Korean Peninsula, which Pentagon officials have said are part of routine, joint military drills with South Korea.
"The U.S. high-handed hostile policy toward the DPRK aimed to encroach upon its sovereignty and the dignity of its supreme leadership and bring down its social system is being implemented through actual military actions without hesitation," the North's statement read.
Meanwhile, a former U.N. official who visited North Korea last year reported that officials there said they could restart the Yongbyon reactor in three months. That is significantly quicker than many U.S. nuclear experts believe a restart would take.
U.S. officials said they did not believe the operation would be a huge engineering challenge.
A restart would, however, be significant, as it would give North Korea the capability to make weapons-grade plutonium again. The reactor was shut down in 2007.
"North Korea's assertion that it intends to bring Yongbyon back online can't be easily written off as an insurmountable hurdle," one U.S. official said.
The Associated Press and NBC News' Marc Smith, Alastair Jamieson, Andrea Mitchell and Becky Bratu contributed to this report.