PYONYANG, North Korea (CNN) -- North Korea took a step closer to easing international fears about its nuclear activities Thursday when it released documents expected to detail its plutonium stockpile to China, Chinese officials confirmed to CNN.

The U.S. State Department also confirmed that the relevent documents had been handed over to China.

The Chinese are now due to pass the papers to the U.S. State Department, which is then expected to announce that North Korea is off the U.S. list of state sponsors of terrorism.

"The United States will implement its obligation to remove the designation of (North Korea) as a state sponsor of terrorism," said Wu Dawei, China's vice foreign minister, before the handover was announced.

Under an agreement hammered out in six-nation talks that included the United States and China, North Korean leaders agreed to provide a full account of the plutonium, and "acknowledge" concerns about its nuclear proliferation and uranium enrichment activities. North Korea will also continue to cooperate with a process to ensure that no further activities are taking place.

The agreement includes additional monitoring to assure Pyongyang receives promised economic and energy assistance in exchange for dismantling its nuclear program.

On Friday, North Korea is set to implode a cooling tower on its Yongbyon nuclear reactor. Nuclear experts have already begun dismantling the plant's main reactor.

But the destruction of the cooling tower is expected to be a powerful public symbol -- as well as a step that would take more than a year to reverse, according to U.S. State Department officials. Watch a report on the step toward curbing N. Korea's nuclear activities »

In a rare move, North Korea has invited international news organizations, including CNN, to witness the tower's destruction.

Speaking last week, U.S. Secretary of State Condoleeza Rice said that once Pyonyang hands over the declaration, U.S. President George W. Bush will announce that North Korea has been removed from the state-sponsored terrorism list and will lift some sanctions against the nation that were levied because of nuclear concerns.

The lifting of the sanctions will have no immediate effect, however, because similar sanctions are in place under other areas of U.S. law, Rice said.

Under the six-party agreement, a 45-day review period will begin after the declaration is handed over. During that time, international nuclear officials will examine the documents to make sure they are accurate and complete.

The six-party talks also included South Korea, Japan and Russia.

During negotiations, the United States ultimately softened demands that North Korea admit to having a highly enriched uranium program and supplying Syria with nuclear technology -- sticking points that had stalled the talks for months.

Rice said the final deal wasn't perfect, but offered the United States its best chance yet to learn about North Korea's nuclear activities.

-- CNN's Zain Verjee contributed to this report

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