North Korea has expanded a uranium enrichment facility and restarted a plutonium reactor it shut down in 2007, Director of National Intelligence of the United States James Clapper said on Tuesday. With this, the country can begin to recover resources to create nuclear weapons within weeks or months. Clapper added that Pyongyang had announced its intention to revamp and restart its nuclear facilities in 2013.

This development increases concerns that besides making technical progress in its nuclear weapons program, North Korea is also expanding its nuclear arsenal. Experts in the US estimate that the country may have about 10 bombs, which can increase to between 20 and 100 by 2020, Associated Press reported.

On Sunday, North Korea had launched a long-range rocket carrying an Earth observation satellite into space. An official in the US said the rocket had stabilised in orbit around the planet, following earlier reports that it was tumbling. However, another official said it is not transmitting any data back. Earlier this year, North Korea claimed to have conducted an underground hydrogen bomb test as well.