The DPRK authorities declared they had performed the first hydrogen bomb test. This information is confirmed by data from seismic stations in South Korea and China, which registered an earthquake with magnitude between 4.2 and 5. "The test means a higher stage of the DPRK's development of nuclear force", — says the message of Korean Central News Agency of North Korea. The explosion caused serious concern around the world — UN Security Council scheduled the emergency meeting for Wednesday, January 6. North Korea first declared it had nuclear weapons in 2005, and after a year performed the first tests. The tests were the reason the country became subject to international sanctions.