The United States says it is counting on China to help convince North Korea to return to six-country talks on its nuclear program.
The North Korean government announced Wednesday it has extracted 8,000 spent fuel rods from a nuclear reactor, prompting new expressions of concern from China and South Korea.
Experts say the fuel rods could be reprocessed to obtain weapons-grade plutonium within a few months.
White House spokesman Scott McClellan told reporters Wednesday China has "considerable influence" on North Korea that could be used to bring the reclusive nation back to talks that have been stalled for nearly a year.
The head of the United Nations atomic agency International Atomic Energy Agency chief Mohamad ElBaradei recently said he believes North Korea may already have as many as six nuclear bombs.