North Korea appears to be running a new fuel fabrication plant in Yongbyon, an apparent sign that the secretive country is making an extensive effort to modernize and restart its nuclear facilities, a U.S. think tank said Monday in a report.

"Commercial satellite imagery has identified facilities at the Yongbyon Nuclear Scientific Research Center that may produce fuel for North Korea's recently restarted 5 MW plutonium production reactor," the U.S.-Korea Institute said on its "38 North" website.

The Washington-based think tank is associated with the Johns Hopkins School of Advanced International Studies.

Earlier this year, North Korea reportedly reactivated the reactor, which was disabled in 2007.

"The availability of fuel is a key factor in the North's ability to operate these facilities," the institute said.

Fuel fabrication is the final stage in nuclear fuel preparation prior to use in a reactor.

The identification of a probable fuel fabrication plant for the 5 MW reactor reinforces the conclusion that the resumed operation of North Korea's nuclear facilities in Yongbyon is "more wide-ranging and extensive than previously understood," said the institute. (Yonhap News)