North Korea's plutonium production for atomic weapons "runs counter" to its nuclear disarmament commitments and "violates" UN Security Council resolutions, the State Department said Tuesday.

Department spokesman Ian Kelly made the remarks after North Korea announced it has produced more plutonium for its atomic weapons program, putting further pressure on the United States to start direct talks.

- It certainly runs counter to the commitment that they made in 2005, and it violates UN Security Council resolutions - Kelly told reporters.

In a 2005 deal with the United States and four other powers, North Korea agreed to scrap its nuclear program and return to the Non-Proliferation Treaty in return for security and diplomatic guarantees and energy aid.

Kelly declined to condemn Monday's plutonium announcement or say whether he believed it ratcheted up simmering tension between President Barack Obama's administration and the reclusive Stalinist regime in Pyongyang.

- What we're focused on with North Korea is getting to the point where we can relaunch the six-party talks, which will get us to our ultimate goal, which is the denuclearization of the Korean Peninsula - he said.

The Obama administration is open to direct talks with North Korea as long as they pave the way for a return to the multilateral negotiations involving the United States, North Korea, South Korea, China, Japan and Russia.

The North quit the six-party talks in April after the United Nations censured its long-range rocket launch, and vowed to restart the nuclear program which it shut down under a 2007 six-party pact.

It conducted an atomic weapons test in May, the second since 2006.

In September, the North also said it was in the final stages of an experimental highly-enriched uranium program -- a second way to make atomic weapons.

On Monday, the official Korean Central News Agency (KCNA) said the communist country "successfully completed reprocessing 8,000 spent fuel rods by the end of August" at its Yongbyon nuclear complex.

- Noticeable successes have been made in turning the extracted plutonium weapon-grade for the purpose of bolstering up the nuclear deterrent - it said.

The comments indicated growing impatience at Washington's delay in accepting Pyongyang's offer of high-level bilateral talks to end the nuclear standoff.

Experts believe the 8,000 spent reactor fuel rods could produce enough plutonium for one or two nuclear bombs, in addition to the North's current stockpile which could perhaps be used to create six to eight weapons.

Kelly said he could not give an assessment of North Korea's plutonium production capabilities.