SEOUL, South Korea – North Korea claimed Tuesday that it has successfully weaponized more plutonium for atomic bombs, a day after warning Washington to agree quickly to direct talks or face the prospect of a growing North Korean nuclear arsenal.

The announcement underlined Pyongyang’s impatience over securing one-on-one talks with Washington, as well as the difficulties in dealing with a regime that resorts to threats and provocations to get what it wants.

Pyongyang’s official Korean Central News Agency said North Korea had finished reprocessing 8,000 spent nuclear fuel rods, which experts say would provide enough weapons-grade plutonium for at least one more nuclear bomb.

The claim may not mean much, since North Korea is believed to already have enough weaponized plutonium for half a dozen nuclear weapons. But the timing – a day after Pyongyang warned it would beef up its nuclear arsenal if the U.S. refused to agree on bilateral talks – shows the communist regime is flexing its atomic might to push Washington to act, analysts said.

“North Korea is trying to ensure off its nuclear might as a way to pressure the U.S. to agree to the talks,” said Kim Yong-hyun, a North Korea expert at Seoul’s Dongguk University.

U.S. State Department spokesman Ian Kelly accused the Pyongyang government of violating its past commitments at international disarmament talks.

“Reprocessing plutonium is contrary to North Korea’s own commitments” at those negotiations and violates United Nations resolutions, Kelly told reporters in Washington. He said the Obama administration was focused on trying to restart stalled six-nation nuclear talks.

North Korea has long sought direct nuclear negotiations with the U.S., believing that it is the easiest, fastest and surefire way of ensuring the survival of the totalitarian regime and win economic concessions to rebuild its moribund economy.

On Monday, North Korea’s Foreign Ministry warned that “if the U.S. is not ready to sit at a negotiating table with the (North), it will go its own way,” an apparent threat to bolster its nuclear arsenal.

Pyongyang has claimed it needs atomic weapons to defend itself against the U.S., which fought against the North during the Korean War in the 50s and has 28,500 troops stationed in South Korea to protect the ally.