An escalating island row between South Korea and Japan has been an annoyance for the U.S., coming at a time when Washington needs all the help it can muster from friends in Asia to counter China's growing military might.

After watching the spat largely in silence over the past few weeks, Secretary of State Hillary Clinton weighed in over the weekend. Following separate meetings with Japanese and South Korean leaders on the sidelines of the Asia-Pacific Economic Cooperation meeting in Vladivostok, her message was clear: The two nations must cool down and get along.

"Specifically with respect to our two good friends and allies, Japan and the Republic of Korea, I raised these issues with both of them, urging that their interests lie in making sure that they lower the temperature and work together in a concerted way to have a calm and restrained approach," she said at a press conference Sunday. "And I think that's being heard."

Whether it has really been heard remained unclear. In Vladivostok, there was no meeting between Japanese Prime Minister Yoshihiko Noda and South Korean President Lee Myung-bak, as the feuding nations decided a face-to-face summit session was a bad idea, after a month-long tit-for-tat over a group of islets called the Liancourt Rocks has left emotions raw. The islands are controlled by South Korea, which calls them Dokdo, and coveted by Japan, where they are known as Takeshima.