The United Nations nuclear agency says its monitors have seen releases of steam and water from North Korea’s Yongbyon Nuclear Reactor, indicating that Pyongyang is trying to restart the facility that could be used for making plutonium for atomic bombs.

“Activities have been observed at the site that are consistent with an effort to restart the 5 megawatt reactor,” said Yukiya Amano, director general of the International Atomic Energy Agency (IAEA), referring to the Yongbyon research reactor.

"However, as the agency has no access to the site, it is not possible for us to conclusively determine whether the reactor has been re-started," he said in a presentation to the IAEA board.

The aged Yongbyon reactor has been out of operation for years.  North Korea destroyed its cooling tower in 2008 as a sign of good faith in nuclear control talks with South Korea, China, the United States, Japan and Russia.  But the Hermit Kingdom usually defies international warnings not to build atomic bombs and long-range missiles.  It’s believed North Korea has enough nuclear material to make 10 weapons.