North Korea in April tried to send a satellite into orbit atop a long-range rocket. The failed launch came after Pyongyang had pledged to suspend military and nuclear testing in exchange for food assistance from the United States.
Satellite imagery company DigitalGlobe uncovered evidence that suggests North Korea is preparing for a launch in the coming weeks. U.S. military sources told CNN they've reviewed the images but didn't think a new launch was imminent. Sources said there were no rockets visible at the site.
Nuclear tests by North Korea in 2006 and 2009 coincided with missile deployments.
A string of assessments this year suggested North Korea was working on rocket developments. This month, the U.S. -Korea Institute at Johns Hopkins University said information gleaned from commercial satellite imagery suggested North Korea had tested at least two rocket motors as recently as September.
The government there said in October that it has missiles in its arsenal that could strike the U.S. mainland and its strategic interests in the region.