A news report said Sunday that it is likely North Korea has sent two American journalists detained last week to the capital of Pyongyang for interrogation.
South Korea's Yonhap news agency quotes sources in China as saying that, considering the significance of the case, it is very likely the two will be questioned by North Korea's security and military agencies. South Korean officials did not confirm the report.
The North's official news agency, KCNA, said Saturday the Americans were taken into custody Tuesday while crossing the North Korea-China border. It said the matter is under investigation.
South Korean media reports said Laura Ling and Euna Lee were detained with their Chinese guide near the Tumen River, along North Korea's border with China.
In Washington, a State Department official said the United States has contacted North Korea about the matter through its mission to the United Nations in New York. The official says Secretary of State Hillary Clinton is very involved in the case.
The journalists were reported to be working on a story on North Korean refugees, many of whom try to escape the country by crossing the river into China. The two were said to have ignored warnings from North Korean guards to stop filming. Reports say a fourth person escaped arrest.
Ling and Lee were working for an online news company, Current TV, that is based in the western U.S. state of California. Current TV was co-founded by former U.S. Vice President Al Gore.
The incident comes at a sensitive time for U.S.-North Korean relations, with the communist state preparing what it calls a satellite launch early next month. The U.S. and South Korea say the launch is a cover for a test of the North's longest-range missile.
Some information for this report was provided by AFP and AP.