HANOI: Nine North Korean asylum-seekers left Denmark's Hanoi embassy for Seoul on Tuesday, just hours before the South Korean president was to arrive for a state visit, a diplomatic source said.

"The nine North Koreans left the Danish embassy this morning and they are now at Noi Bai International Airport checking in before flying to Singapore and then Seoul," the Vietnamese diplomatic source told AFP, asking not to be named.

A Danish diplomat declined to comment when asked about the case.

The South Korean foreign ministry and other agencies also declined, which is their usual position on North Korean refugees abroad.

The nine entered the Danish compound on September 24 hoping to reach South Korea, Kim Sang-Hun, an activist who said his group helped them reach the embassy, told AFP earlier.

According to the Vietnamese diplomatic source, they were to fly out at 0630 GMT, just 35 minutes before the scheduled arrival of South Korean President Lee Myung-Bak at the same airport.

Lee's first official visit to Vietnam, a former foe turned key business partner, lasts until Thursday.

Officials said the visit aimed to boost ties, despite a recent hiccup in relations relating to the Vietnam War.

Leonid Petrov, a lecturer in Korean studies at the University of Sydney, said earlier that he was sure the case of the asylum-seekers would be resolved without damaging Vietnam's relations with either North or South Korea.

The asylum-seekers had spent nearly a month living under a blue tent on the Danish embassy compound.

They included a doctor and his wife, a mother and her 13-year-old daughter, and a woman who had worked as a "virtual slave" in a Chinese karaoke club, said the activist group.

They were the latest in a series of North Koreans who have fled the impoverished and isolated country and sought asylum at various Hanoi embassies in recent years.

The South Korean government in 2004 chartered a plane to fly out 468 North Korean refugees sheltering in its Hanoi embassy. The airlift angered Pyongyang and embarrassed Hanoi.

South Korea has taken in thousands of people who have fled impoverished and isolated North Korea on an "underground railroad" of illegal border crossing and safe houses that usually leads via China to Mongolia or Southeast Asia.

With the asylum-seekers gone, Lee and his Vietnamese counterpart, Nguyen Minh Triet, will be free to focus on signing a package of deals and upgrading ties to a "strategic cooperative" relationship after reportedly resolving a dispute linked to the Vietnam War.

While noting that relations have warmed quickly since normalisation of ties in 1992, Vietnam's ambassador to Seoul, Pham Tien Van, asked South Korea not to repeat a "mistake" related to the war.

"If South Korea beautifies its participation in the Vietnam War, it would be an act harming the feelings of Vietnamese people and rubbing salt into their wounds," he said in an interview with South Korea's Yonhap news agency.

South Korea sent 300,000 troops to fight alongside the United States during the Vietnam War, which ended in 1975 with the country's reunification.

South Korea's Ministry of Patriots and Veterans Affairs said last month it would push for legislation to give economic compensation and other benefits to Vietnam War veterans, saying they "worked for world peace", Yonhap reported.

According to diplomatic sources cited by Yonhap, Vietnam's uneasiness over the proposed legislation led Seoul's foreign minister, Yu Myung-Hwan, to make a rushed trip to Hanoi.

But the issue has now been resolved, the Vietnamese ambassador told Yonhap.