South Korean military officials deliberately withheld information from the president about the arrival of new launchers for a controversial US anti-missile system, his office said Wednesday.

South Korean media on Monday warned of a "Trump risk" threatening the alliance between Washington and Seoul amid high tensions over the North's weapons ambitions.

Seoul on Friday brushed aside US President Donald Trump's suggestion that it should pay for a $1 billion missile defence system the two allies are installing in South Korea to guard against threats from the North.

US troops began delivering a missile defence system that has infuriated China to a deployment site in South Korea Wednesday, amid heightened tensions over the North's nuclear ambitions.

Hundreds of South Koreans protested Saturday against the deployment of a US missile defence system, a day after the visiting US Secretary of State reiterated that its installation would go ahead.

North Korea's nuclear and missile capabilities are accelerating at an "unprecedented" pace, the South's acting president said Monday, urging the swift deployment of a US anti-missile system that has infuriated Beijing.

Two huge US bombers flew over South Korea Tuesday in a show of force against the North as a top US envoy said China must help close loopholes in sanctions ...