TOKYO - THE top US negotiator in talks to rid North Korea of nuclear weapons said on Tuesday that Pyongyang must agree to a verification of its disarmament activities and the deal must be put in writing.

North Korea agreed last year to disable its nuclear reactor in exchange for aid. But negotiations have since stalled after the Stalinist state denied it agreed to allow inspectors to take samples from its nuclear complex to verify past nuclear activities.

The United States and other negotiating partners, however, have said the disarmament-for-aid pact hinges on the ability to confirm that the North has fully disclosed the extent of its atomic programs.

Assistant Secretary of State Christopher Hill said on Tuesday he wants to see the a list of measures clearly stated in a written agreement.

'Whether that takes one document, two documents, three documents, we don't know. The important point is to make it clear so there are no misunderstandings,' Mr Hill told reporters as he arrived in Tokyo.

Mr Hill is travelling in Asia for a series of meetings ahead of the next round of international disarmament talks on Dec 8 in Beijing.

Mr Hill was to hold talks with his Japanese counterpart Akitaka Saiki later on Tuesday. He plans to hold talks on Wednesday with Mr Saiki and their South Korean counterpart before heading to Singapore to meet with North Korean officials. -- AP