The head of the UN's nuclear watchdog said Thursday that continued activity has been observed at the Yongbyon light water reactor in North Korea.  

International Atomic Energy Agency(IAEA) Director General Yukiya Amano told board members Thursday his agency has seen activities consistent with the fabrication of reactor components and the possible transfer of these components into the reactor building. 

The IAEA chief said further activities were observed near the Kuryong River which may be related to changes to cooling infrastructure.

However, Amano said that it was difficult to ascertain the exact nature without inspectors being able to access the site.

He said the IAEA is willing to send inspectors to the North at any time, and urged North Korea to fully comply with its obligations under relevant resolutions of the UN Security Council and of the IAEA board.