(VOVworld) - Cooperation between China and the US is "vital" to ensure global nuclear security, said Thomas Countryman, US assistant secretary of state for international security and nonproliferation, on Monday.

The Fuqing nuclear power plant is under construction in China. (Photo: chinadaily)

He told reporters ahead of the fourth Nuclear Security Summit that the two countries worked successfully on last year's comprehensive nuclear agreement with Iran and on the recent UN Security Council sanctions resolution against North Korea's nuclear tests and missile launch. He highlighted ever closer bilateral ties in preventing the spread of the technology used to make nuclear weapons.

Earlier this month, the Nuclear Security Center of Excellence, the largest nuclear security center in the Asia-Pacific region, opened in Beijing.