Donald Trump unexpectedly suspended “war games” on the Korean peninsula yesterday as he convinced Kim Jong-un to back “complete denuclearisation” in a written agreement.

The US president said joint US-South Korean military exercises were “very provocative” and “tremendously expensive”, attacking a policy his own administration has pursued until now.

Mr Trump also floated the possibility of one day pulling America’s tens of thousands of troops out of South Korea, though he said the move was not currently under consideration.

Both policy changes have been long-called for by the North Korean government but repeatedly rejected by the Trump administration in the past.

The announcements appeared to catch the South Koreans by surprise, with their president’s spokesman calling for a “more clear understanding” of what Mr Trump meant.

Video: Key moments from Trump's Press conference