US President George W. Bush and Chinese leader Hu Jintao agreed during a phone call Wednesday to maintain pressure on North Korea to honor its pledge to dismantle its nuclear weapons, the White House said.

Bush and Hu "pledged to continue to work closely with the other six-party partners in urging North Korea to deliver a complete and correct declaration of all its nuclear weapons programs, and nuclear proliferation activities and to complete the agreed disablement" the White House said in a statement.

North Korea has refused to make a complete declaration of its nuclear weapons program and its alleged proliferation activities as part of an aid-for-disarmament deal agreed to by six parties — the United States, China, the two Koreas, Japan and Russia, officials said.

Bush "expressed appreciation to president Hu for the important role China has played within the six-party framework," the statement read.

The declaration was supposed to have been made by the end of 2007 under the deal, which would reward North Korea with energy aid as well as diplomatic and security guarantees by the United States and others.

North Korea, which has already closed its main nuclear reactor complex and is in the process of disabling it, submitted a list last November but the United States says it has not accounted fully for a suspected uranium enrichment program and allegations of nuclear proliferation to Syria.