Chief diplomats from the United States, South Korea and Japan on Monday started their trilateral talks on the situation of Korean peninsula.

The meeting is held at the U.S. State Department in Washington, grouping U.S. State Secretary Hillary Clinton, South Korean Foreign Minister Kim Sung-hwan and Japanese Foreign Minister Seiji Maehara.

In the opening remarks, Clinton said the talks took place "at a time of grave concern" in northeast Asia.

After the opening remarks, the three turned into a closed-door meeting.

Tensions remain high on the Korean Peninsula after the Democratic People's Republic of Korea and South Korea exchanged artillery fire on Nov. 23, leaving four South Koreans dead and more than a dozen others injured.