North Korea made its first acknowledgment of an H1N1 outbreak with a short dispatch in state media citing nine confirmed cases in northwestern Sinuiju on the Chinese border and in Pyongyang, the capital.
The official Korean Central News Agency reported that a quarantine system to prevent the spread of the disease was in place and that medical treatment was under way.
The KCNA report did not mention any virus-related deaths or say how the flu spread to North Korea, which maintains strict control over its citizens' movements and is selective about who can enter the country.
The World Health Organization, which has an office in Pyongyang, said in a statement later Wednesday that no deaths due to swine flu had yet been recorded in North Korea. WHO said nine North Koreans have been confirmed as having swine flu since Dec. 3, when a school child in Sinuiju tested positive for the virus.
The WHO statement also said that "active surveillance" was under way in North Korea to contain the virus's spread.
However, a Seoul-based civic group that first reported the outbreak earlier in the week said swine flu killed some 50 people in North Korea since early November.
Lee Seung-yong, a project coordinator for Good Friends, which sends food and other aid to North Korea, refused to provide the source for the information.
He said North Korea has taken emergency measures, including quarantining those who had contact with patients with H1N1. However, with less than sanitary conditions and a lack of medicine, the virus spread rapidly.
North Korean health authorities have blamed traders who travel between North Korea and China for the outbreak in Sinuiju, he said.
Officials in the South Korean government said they could not immediately confirm the reports about H1N1-related deaths in North Korea.
Swine flu has killed more than 8,700 people worldwide since the first outbreaks in Mexico in April, according to the WHO.
In South Korea, which has nearly twice the population of the North, the virus has killed 117 people. Health authorities aim to have 7.5 million students in primary through high school vaccinated by the end of the year, the Health Ministry said.
Flooding and economic mismanagement in the 1990s destroyed the country's farming sector, and North Korea now relies on outside handouts to feed its people. Nuclear defiance has further tightened U.N. sanctions on the regime.
On Tuesday, South Korean President Lee Myung-bak offered unconditional help to North Korea after hearing about the reported outbreaks. He ordered his Cabinet to look into the reports and find ways to send swine flu medication as humanitarian aid.
The Unification Ministry in Seoul said Wednesday that it plans to offer to discuss the matter with North Korea. "We will provide aid as early as possible, without any conditions," ministry spokesman Chun Hae-sung said.