South Korea's point man on the North cautioned Monday that it would be premature to declare North Korea a nuclear power despite its claim to having atomic weapons.

Unification Minister Chung Dong-young noted North Korea (search) has yet to conduct a nuclear test, unlike other nuclear powers such as India and Pakistan.

"I believe it is early for us to call the North a nuclear state," when it has not been independently confirmed, Chung said in a speech to parliament.

The secretive communist nation announced Thursday that it has built nuclear weapons and was staying away from international disarmament talks.

The claim dramatically raised tensions in the two-year standoff over the North's nuclear ambitions. He said even senior U.S. officials who have pushed for a hard line on North Korea have said it's not clear if North Korea really has such arms.

Chung, the South's point man on Pyongyang, noted Korea has said it has atomic weapons at least 10 times since 2003.

"It's definite that North Korea possesses 10 to 14 kilograms of plutonium that can make one or two nuclear weapons," he said. However, he said there was no "conclusive evidence that North Korea made plutonium bombs" with the material, but that other countries suspect North Korea has one or two nuclear bombs.

Chung urged North Korea to embrace the spirit of denuclearization, saying it will "be difficult for North Korea to become a trusted member of the international community if it holds and develops nuclear weapons."

Also Monday, South Korean President Roh Moo-hyun (search) received a report from his top security aides about the North's latest statement on its nuclear program, and ordered them to "carefully handle" the issue, Roh's office said without giving further details.

Opposition lawmakers were skeptical about Chung's optimism over the nuclear situation and charged that the government was not pushing the North hard enough to return to the negotiating table.

"When a father wants his son to quit smoking ... shouldn't he stop giving his son money to buy cigarettes?" said Hong Joon-pyo of the main opposition Grand National Party. "Peaceful resolution is good, but the government lacks concrete measures."

South Korean Foreign Minister Ban Ki-moon was scheduled to meet Secretary of State Condoleezza Rice (search) on Monday in Washington amid U.S efforts to coax North Korea back to six-nation talks on ending the North's nuclear program.

North Korea accuses the United States of planning to invade and says it needs nuclear weapons to defend itself. Washington denies it intends to attack and insists that the communist North return to the talks, which also involve South Korea, China, Russia and Japan.

The parties have also urged Beijing — Pyongyang's last major ally and a key supplier of food and energy to the impoverished country — to use its influence over North Korea. China pledged over the weekend to try to revive the talks and on Monday said it was reaching out to Russia for help.

"The Chinese side will make the utmost effort to work with the related parties, including Russia, to promote the process of the six-party talks," Chinese Foreign Minister Li Zhaoxing told his Russian counterpart Sergey Lavrov in a telephone call, the Chinese government said.