Beijing  - North Korea would submit a formal declaration on its nuclear programme to China on Thursday, a Chinese official said, in a move that could prove a key step towards ending the programme.

Wu Dawei, China's chief negotiator at six-party talks on the nuclear programme, said the United States would also take reciprocal steps agreed to last year between the six nations.

"In the spirit of the October 3, 2007 six-party agreement, on June 26, 2008, the DPRK will submit its nuclear declaration to the chair of the six-party talks," Wu told reporters, using North Korea's official name of the Democratic People's Republic of Korea.

"The parties agreed that the declaration will be subject to verification and there is agreement within the parties on a set of principles to guide the establishment of a verification regime," he said.

China has chaired the six-party negotiations, which also involve North Korea the United States, South Korea, Russia and Japan.

The United States would implement its obligations under the six-nation agreement to end its designation of North Korea as a state sponsor of terrorism and terminate the application of the Trading with the Enemy Acts to North Korea, Wu said.

South Korean media said North Korea's declaration would only list the country's plutonium stock.

North Korea was not expected to reveal information on the number of nuclear weapons at its disposal, South Korea's public broadcaster KBS and the news agency Yonhap reported Wednesday, citing sources in Seoul.

US State Department deputy spokesman Tom Casey said the United States expected not only information about North Korea's plutonium programme, but also about a suspected campaign for uranium enrichment and the proliferation of nuclear weapons.

Both plutonium and highly-enriched uranium can be employed to build nuclear weapons.

According to the six-party agreement, North Korea's complete declaration should have been presented by the end of 2007.

In exchange for its cooperation, the other five parties promised North Korea substantial economic and energy aid.

The US agreed to drop the internationally isolated state from its blacklist of terrorism-supporting countries and to lift trade sanctions once the declaration was submitted. (dpa)