North Korea is likely to prepare a new underground nuclear test explosion, the Russian Trud daily said on Thursday citing Japanese Kyodo news agency. In 2009, Pyongyang conducted its second underground nuclear test explosion and test-launched at least six short-range surface-to-air and anti-ship missiles in defiance of previous UN resolutions. The satellite images taken by DigitalGlobe Inc., a U.S. company majoring in geographical imagery, show some activity at the site in North Hamgyong Province where Pyongyang conducted its second nuclear test, Trud said. A U.S. military expert told the news agency that at least six vehicles and objects resembling equipment appeared on the test ground. The satellite photos also captured a pile of soil allegedly appearing after digging a tunnel for the underground nuclear test. Pyongyang is already under a number of UN sanctions over its first nuclear test carried out in 2006.