President Donald Trump called on US military leaders to resume testing US nuclear weapons in order to keep pace with other countries such as Russia and China.
"Because of other countries testing programs, I have instructed the Department of War to start testing our Nuclear Weapons on an equal basis," he wrote on social media just before meeting with Chinese President Xi Jinping in South Korea
Trump's post did not include details of how the tests would occur, but wrote the "process will begin immediately".
It is necessary for the US to keep pace with weapons programmes in China and Russia, the president says.
www.bbc.co.uk