Obama calls South Korea, Japan on North Korea's nuclear test

President Barack Obama has called the leaders of both South Korea and Japan to discuss how the international community should respond to North Korea's nuclear test.

The United Nations has condemned the North for conducting Monday's underground nuclear blast.

The White House says that Obama placed separate calls to the leaders of South Korea and Japan on Monday night.

Obama and South Korean President Lee Myung-bak agreed that the test was a "reckless violation" of international law that compels action in response.

Obama and Japanese Prime Minister Taro Aso agreed to intensify their coordination of efforts with South Korea as well as with China and Russia.