North Korea's Yongbyon reactor 'nearing operation'

Steam has been seen rising from North Korea's Yongbyon nuclear facility, suggesting that the reactor has been restarted, a US institute says.

The colour and volume of the steam indicated that the reactor was in or nearing operation, the institute said.

Pyongyang vowed to restart facilities at its main Yongbyon nuclear complex in April, amid high regional tensions.

The reactor can produce plutonium, which North Korea could use to make nuclear weapons.

Lucy Williamson reports from Seoul.