A U.S. research institute says that North Korea seems to be on the path to complete the construction of a nuclear reactor by the end of next year.
The Washington-based Institute for Science and International Technology said Tuesday that imagery taken in May and June shows cranes, and a dome next to a sizeable structure, which is thought to be a reactor building.
The institute says on its website that major external work on the reactor and the adjacent building appears to be "complete with most of the activity occurring inside the reactor building."
The images also show construction in other areas.
An expert who evaluated the images of the Yongbyon facility, taken by commercial satellite, estimated that the reactor could be completed in the second half of 2013.
But the institute said it may take another 1 to 2 years before the new facility becomes operational.
North Korea's main nuclear site is in Yongbyon, about 100 kilometers north of the capital, Pyongyang.
Its work on the new reactor was first revealed in 2010. Officials have said they want to build an experimental light-water reactor for peaceful purposes. But it is generally believed that Pyongyang is working to continue to develop nuclear arms. The communist country has already conducted two nuclear tests.
Pyongyang agreed earlier this year to suspend its nuclear programs and missile tests in exchange for aid. But the deal collapsed after North Korea launched a rocket in April despite protests from the international community.