US

Monitors report unusual seismic activity in North Korea

FILE - In this Oct. 10, 2015, file photo, North Korean leader Kim Jong Un salutes at a parade in Pyongyang, North Korea. South Korean and international monitoring agencies reported Friday, Sept. 9, 2016 an earthquake near North Korea's northeastern nuclear test site, a strong indication that Pyongyang had detonated its fifth atomic test explosion. (AP Photo/Wong Maye-E, File)

FILE - In this Oct. 10, 2015, file photo, North Korean leader Kim Jong Un salutes at a parade in Pyongyang, North Korea. South Korean and international monitoring agencies reported Friday, Sept. 9, 2016 an earthquake near North Korea's northeastern nuclear test site, a strong indication that Pyongyang had detonated its fifth atomic test explosion. (AP Photo/Wong Maye-E, File)  (The Associated Press)

A European monitoring agency is reporting a 5.0 magnitude quake near North Korea's northeastern nuclear test site. There was no immediate confirmation of a nuclear test, which such seismic activity has previously indicated.

South Korea's Defense Ministry said Friday it could not immediately confirm the cause, and the country's weather agency said it was analyzing what might have happened. But the U.S. Geological Service reported an "explosion" in the area.

North Korea conducted its fourth nuclear test earlier this year, part of its push for a nuclear-armed missile that could one day reach the U.S. mainland.