"North Korean Officials Cross the Border To Arrest US Journalists,"

reports the Times (London):

Security officials from North Korea have detained two Korean-American journalists [Laura Ling and Euna Lee], apparently while they were on the Chinese side of the border and filming into the closed Stalinist state.

The report by South Korea's YTN channel quoted a South Korean government official as saying that the guards had crossed the border into Chinese territory to arrest the pair after they ignored warnings to stop filming.

The two women worked for an online news company based in California, the report said....

If the North Korean guards did cross the Yalu or the Tumen rivers that demarcate the border, this could prove extremely embarrassing for Beijing, which is the only major ally of isolated North Korea and its main source of economic aid....

More from ABC News, quoting a State Department spokeswoman:

We are aware through reliable channels on the morning of March 17, that two American citizens were taken into custody across the Tumen River from China into North Korea by what appeared to be North Korean border guards....

We are working with the Chinese government in the area to get information on the whereabouts and welfare of the Americans in question. We have also been in touch with North Korean authorities to express our deep concern about this situation. We have also been in touch with our protecting power, the Swedish Embassy in Pyongyang....

"Protecting power" is of course a diplomatic term of art here, rather than a claim about any likely forceful protection.