London: The United States has described the prospect of North Korea restarting a mothballed atomic reactor as "extremely alarming".
North Korea said it would reactivate all facilities at its main Yongbyon nuclear complex to ease its electricity shortage and strengthen its nuclear capability. The reactor was shut down in 2007 as part of international nuclear disarmament talks that have since stalled, reports the Guardian.
The move came a day after Pyongyang announced a "new strategic line" focusing on its nuclear programme and economy.
The Yongbyon announcement follows repeated warnings from the North that it is on a war footing with South Korea. The regime has also threatened nuclear strikes against the US mainland and its overseas military bases, though experts are convinced it is still several years away from developing the necessary technology.
But the Obama administration has said that it would take time between the announcement and the North's ability to restore its nuclear programme.
Duyeon Kim, a North Korea and nuclear arms specialist at the Centre for Arms Control and Non-Proliferation in Washington, estimated it would take North Korea at least a year to reverse the steps taken in 2007.
A US state department spokeswoman, Victoria Nuland, said the US will not accept North Korea as a nuclear state, and added that re-activating Yongbyon would be a clear violation of the North Korea's international obligations and the commitments it made at that time.
The UN secretary general, Ban Ki-moon, said he feared North Korea was on a collision course with the rest of the world that could lead to war. Ban, a former South Korean foreign minister, said the crisis had "gone too far" and called for dialogue to ease tensions on the peninsula.
Jay Carney, the White House press spokesman, said the US is regularly reaching out to Beijing and Moscow to encourage them to do more to restrain the North Koreans.
US secretary of state, John Kerry, said that restarting Yongbyon would be a violation of international obligations. He added that what Kim Jong-un has been choosing to do is provocative, dangerous and reckless. Kerry reiterated that the US will do what is necessary to defend itself and its allies, Korea and Japan.