By Charles Scanlon
BBC News, Seoul
An American delegation led by the governor of New Mexico and former ambassador to the UN, Bill Richardson, has arrived in North Korea.
Mr Richardson is an experienced diplomatic trouble-shooter
Mr Richardson said he aims to secure the release of remains of US servicemen killed in the Korean war in the 1950s.
The trip comes as the state department says it has cleared a major obstacle for progress in getting North Korea to end its nuclear weapons programme.
The Democrat is making the visit with the Bush administration's approval.
Mr Richardson is well known as a diplomatic trouble-shooter with much experience of North Korea.
He went to Pyongyang with the approval of the Bush administration even though he is a contender for the Democratic presidential nomination.
He was accompanied on the visit by Victor Cha, one of the president's top advisers on the region.
Mr Richardson said his main aim was to bring back the remains of US servicemen killed in the Korean war.
The bank has been on a US blacklist since September 2005
Co-operation on the returns broke down two years ago as tensions rose over North Korea's development of nuclear weapons. The US is now trying to improve ties in an effort to contain its nuclear arsenal.
The delegation has said it is not planning to negotiate over the nuclear programme although the North Koreans are expected to bring it up.
North Korea agreed in February to shut down its one operation nuclear reactor in return for economic aid.
But diplomats say it is unlikely to meet the mid-April deadline because of a dispute over financial sanctions.
The US says it has now cleared the way for the release of North Korean money that has been frozen in a Macau bank account.