"What we need to do is to make sure that the verification protocol is one that clarifies issues so that there won't be any misunderstandings, " the diplomat, Christopher Hill, told reporters after arriving for talks with his North Korean counterpart, Kim Kye-gwan.
"We need some specificity on this protocol, we had a lot of discussions about it and I think we do have an understanding on how to go forward," he said.
The two days of talks are expected to set the tone for a broader meeting in Beijing next week of six regional powers that also include South Korea, China, Japan and Russia.
Analysts say North Korea, sensing U.S. President George W. Bush's team may want a diplomatic success before leaving office in January, may try to wring concessions in Beijing.
Sampling Issues
The most recent stumbling block in a disarmament-for-aid deal the North reached with the five other powers is Pyongyang's objection to allowing international inspectors to take nuclear samples out of the country for testing.
Hill has been criticised by conservatives in Washington for being too flexible with North Korea and not obtaining detailed information from Pyongyang about its suspected programme to enrich uranium for weapons, or for proliferating technology to countries such as Syria.
President-elect Barack Obama has mostly supported Bush's North Korea diplomacy. The one thing Obama appears willing to consider, and which analysts say North Korean leader Kim Jong-il dearly prizes, is the first direct talks with a U.S. president.
"Further discussion on verification would only be possible after Obama takes office and sets it as a priority. Until then, the U.S. will likely remain in limbo on North Korean issues," said Kim Seung-hwan, with the Centre for Strategic and International Studies in Seoul.
Impoverished North Korea has spent the best part of two decades goading U.S. presidents and regional powers into handing over billions of dollars to curtail, but never actually end, its nuclear weapons programme, which is considered one of Asia's biggest security threats.
The North has largely cut ties with South Korea, once a major aid donor, in anger at the tough policies of its conservative president who took office in February. In the meantime, it has won concessions in the nuclear talks that benefit its economy.
