The US is likely to send Jack Pritchard, a Koreas expert

The move appears to signal the secretive Communist state's readiness to resume security talks after an 18-month break.

It has also agreed to search for Japanese nationals believed to have been kidnapped decades ago, after talks between the two countries' Red Cross officials in China.

The diplomatic progress follows a visit by a South Korean presidential envoy earlier this month during which Pyongyang signalled its willingness to move forward on both these issues.

Yet to respond

While Washington has not responded officially to the invitation to send its envoy to the North, it has stated in the past that it is ready to meet North Korea at any time and in any place to resume the talks.

The US is likely to send senior State Department official Jack Pritchard, the BBC's Jon Leyne reports from the department in Washington.

US relations with North Korea have been in difficulty since President George W Bush took office at the beginning of last year.

President Bush angered Pyongyang with his 'axis of evil' comments

After Mr Bush showed little initial enthusiasm for continuing the security talks begun under the Clinton administration, North Korea refused to resume them when invited to do so last June.

Things were not helped when the country was designated part of an "axis of evil" by President Bush, our correspondent says.

Washington wants to stop North Korea being able to produce weapons of mass destruction and also to reduce the huge army facing its ally, South Korea.

In return, the North Koreans will be looking to extract as much aid as they can to keep alive their deeply troubled economy.

Earlier on Monday, Reuters news agency reported that North Korean leader Kim Jong-il had invited former US President Bill Clinton to play a mediating role.

Japanese deal

North Korea's agreement to search for the allegedly kidnapped Japanese comes after two days of talks at a hotel in Beijing - the first in two years between the two countries' Red Cross officials.

The Communist state also agreed to allow Japanese wives of North Koreans to visit Japan.

In return, Japan is to search for Koreans taken to Japan before 1945.

Tokyo says North Korea abducted 11 Japanese nationals 25 years ago to train them as spies or to teach North Korean agents the Japanese language and customs.

North Korea, for its part, says that 259 North Koreans went missing in Japan before and during World War II.

Japan colonised the Korean Peninsula between 1910 and 1945, forcing hundreds of thousands of Koreans into slave labour and prostitution.

Stranded

Tuesday's agreement also means that about 1,800 Japanese women married to North Koreans can now visit their home country.

They moved to North Korea with their ethnic Korean husbands between 1959 and 1982.

The dispute over the missing Japanese and the wives has stood in the way of normalising relations between the two countries for years.

A new round of talks, at an undisclosed location, was agreed for June.