WASHINGTON (CNN) -- Two U.S. journalists have been taken into custody, apparently by North Korean border guards, in the area of the Tumen River marking the border between North Korea and China, the U.S. State department said.
North Korean Prime Minister Kim Yong Il (left) visits Chinese President Hu Jintao in Beijing on Thursday.
A State Department official tells CNN the United States is working with the Chinese government on the case and has expressed Washington's concern to North Korea through the Swedish Embassy in the North Korean capital, Pyongyang. Sweden represents the United States in North Korea since the United States does not have diplomatic relations with the North.
Media reports have identified the women as Laura Ling and Euna Lee, from the online news outlet called Current TV, co-founded by former Vice President Al Gore. The State Department is not confirming the women's names and is not saying where the women are being held.
Gore has asked Secretary of State Hillary Clinton for help, a senior administration official told CNN. "She is very engaged and is following it closely," the official said.
CNN has learned that the two were a part of a group of four who were filming near the Tumen River area, on the border between China and North Korea. As the North Korean guards tried to arrest them, an American male and a Chinese driver fled; the two women were caught. Watch a report on the arrests »
The arrest was made early Tuesday.
Officials said the State Department is trying to pin down exactly whether the journalists were on the Chinese side of the border or on the North Korean side when they were caught.
The women were caught in the middle of the frozen Tumen River, where the border between the two countries is not clearly marked, a senior administration official said.
In addition to working through the Swedish embassy in Pyongyang -- the U.S. protective power in the absence of formal U.S.-North Korean ties -- Washington is also seeking help from the Chinese.
A Chinese official told CNN Beijing is investigating. U.S. officials have also reached out to the North Korean mission to the United Nations, a common way of communicating with Pyongyang.
Before they went into North Korea, the group was on a fact-finding mission to South Korea. They talked to a few local journalists, then enlisted the help of a South Korean pastor who helps North Korean refugees flee the North.
Tensions with North Korea have been high for months, as the North has announced it is preparing to launch a missile carrying what it describes as a communications satellite. The United States and several other Western governments say that the missile could be used to launch a nuclear warhead and that any launch would violate U.N. Security Council resolutions. The missile, a Taepodong-2, is thought to have an intended range of about 4,200 miles (about 6,800 kilometers).
North Korea accuses the United States and South Korea of threatening its security by engaging in military exercises, which end March 20.
The incident comes as North Korean Prime Minister Kim Yong Il is visiting Beijing.