North Korea conducted a nuclear test.

SyuzhetyYadernoe disarming North Korei07.05.2009KNDR suspected of preparing new nuclear test oruzhiyaSevernaya Korea on Monday conducted a nuclear weapons test, transmits Agence France-Presse, referring to the official statements of the South Korea. Official Pyongyang also confirmed information on the successful nuclear tests.
According to the Korean Central News Agency (KCNA), the tests that were conducted under the ground, completed "successfully". Where exactly were conducted nuclear tests, North Korean agency did not specify.
According to South Korean news agency Yonhap, the test was conducted at 04:54 (Moscow time) near the town of Kilchzhu in the north-eastern North Korea. In response to DPRK's nuclear test, South Korean President Lee Myung Bak convened an emergency meeting of the National Security Council.
Reported that in the area of the alleged nuclear test was recorded "artificial" earthquake of magnitude 4.5. The earthquake's epicenter, said CNN, referring to the U.S. Geological Survey (USGS), located at a depth of ten kilometers.
Remember, the first tests of nuclear weapons the DPRK in October 2006 also received at the test site is located near the Kilchzhu. Following the nuclear tests the United Nations imposed sanctions on Pyongyang, a number of, inter alia, prohibiting foreign companies to supply the DPRK materials used in nuclear development.
In April 2009, the DPRK conducted a successful launch of satellites. Western States, especially the United States, accusing Pyongyang that under the guise of launching a satellite North Korea tested ballistic missiles. Shortly after this action by North Korea has condemned the UN Security Council. The DPRK, in turn, announced the resumption of work at the main nuclear plant to produce weapons-grade plutonium.