N. Korea: We've built more nukes
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(CNN) -- North Korea is claiming to have boosted its nuclear weapons arsenal to counter what it says is the threat of imminent invasion by the United States and South Korea.
The secretive communist state's official Korean Central News Agency reports on its Web site that current U.S.-South Korea military exercises, which began Saturday, are escalating tensions on the peninsula and are ultimately aimed at launching a pre-emptive strike on the North.
"The reality goes to prove that it is very just for the DPRK (North Korea) to have opted for bolstering its self-defensive nuclear arsenal in order to protect the peace of the country and the fate of the nation from the U.S. moves for aggression," the Web site says.
"The DPRK's nukes serve as a powerful deterrent to keep the balance of forces in Northeast Asia, prevent the outbreak of a new war and preserve peace," it said.
A later statement on the Korean Central Broadcasting Station said the North had "taken a serious measure by increasing its nuclear arms arsenal in preparation for any invasion by enemies," according to a report by South Korea news agency Yonhap.
No details were released by Pyongyang of what the nuclear measures entailed.
The United States has around 33,000 troops based in South Korea and conducts twice-yearly war exercises with its Asian ally.
The extent of North Korea's nuclear capability is not widely known as its supposed devices have not been tested.
However, the U.S.'s Central Intelligence Agency believes Pyongyang has perhaps two nuclear bombs and enough weapons-grade plutonium to make several more.
North Korea has frequently claimed it would increase its nuclear deterrent in response to the perceived threat of invasion by the United States, but the Monday announcement appeared to be the first time Pyongyang has claimed actually to have done so.
The United States has repeatedly denied it intends to attack North Korea, a position reiterated by U.S. Secretary of State Condoleezza Rice during her visit to China earlier this week.
The United States, Russia, Japan, South Korea and China began a joint diplomatic effort with North Korea in 2003 aimed at persuading Pyongyang to abandon its nuclear program, but it has been stalled since North Korea refused to attend the last scheduled round of talks in September.
Last month, Pyongyang declared it had nuclear weapons and would indefinitely continue its boycott.
Speaking in Beijing on Monday, Rice said Washington would "have to look at other options" if the North did not return to the talks.
"Obviously, everyone is aware of the other options in the international system," Rice said.
"Of course if we cannot find a way to resolve the North Korean issue in this way (through six-party talks), then we will have to find other means to do it."
Rice, who met Chinese leaders during the final leg of her six-nation Asian tour, also asked Beijing for more help in bringing North Korea back to the negotiating table.
"We need to resolve this issue, it cannot go on forever," Rice said earlier.
The North Korean statement also comes as the country's premier, Pak Pong-ju, heads to China for talks that will likely touch on the nuclear crisis.