(CNN) Fresh satellite images of North Korea obtained by CNN show new work and the expansion of buildings associated with the production of long-range intercontinental ballistic missile launchers in Pyongsong, North Korea.

The March 16 factory in Pyongsong produces trucks for North Korea's military and was involved in modifying launchers imported from China and producing domestic vehicles for North Korea's ICBM programs, according to Jeff Lewis, the director of the East Asia Nonproliferation Project at the Middlebury Institute.

Lewis told CNN that North Korea in the past has been forced to import the heavy-duty chassis strong enough to transport massive missiles.

"The expansion of the factory may represent a growing capability of North Korea to produce these trucks domestically," Lewis said in explaining the significance.

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