The US and South Korea are reportedly set to halt joint military exercises as early as this week, just days after Donald Trump promised to halt something he said was both costly and “very provocative” to Kim Jong-un.

During his summit with the North Korean leader last week in Singapore, Mr Trump said he wanted to halt the exercises and even suggested he wanted to bring home the 28,000 US troops stationed on the peninsula.

“Under the circumstances that we’re negotiating a very comprehensive, complete deal I think it’s inappropriate to have war games. It is something that [North Korea) very much appreciated,” he said.

Referring to the cost of the exercises, he added: “We fly in bombers from Guam. That’s a long time for these big massive planes to be flying to South Korea to practice and then drop bombs all over the place and then go back to Guam. I know a lot about airplanes. It’s very expensive.”

While some critics of Mr Trump he had given up the concession long demanded by North Korea with nothing in exchange, others said it was worth it to continue to negotiate with Pyongyang.

Both South Korea and the US military seemed caught off guard by the announcement, but secretary of state Mike Pompeo subsequently flew to South Korea to brief officials on Mr Trump’s summit with Mr Kim.

On Sunday, the South Korean news agency Yonhap said an announcement on the exercises’ suspension was expected to be made this week. It said they would be restarted if North Korea failed to press ahead with its undertaking to work towards denuclearisation.

“Holding back the “war games” during the negotiations was my request because they are VERY EXPENSIVE and set a bad light during a good faith negotiation. Also, quite provocative. Can start up immediately if talks break down, which I hope will not happen,” Mr Trump tweeted.

He added: “The denuclearisation deal with North Korea is being praised and celebrated all over Asia. They are so happy! Over here, in our country, some people would rather see this historic deal fail than give Trump a win, even if it does save potentially millions & millions of lives.”

Reuters said that immediately after Mr Trump announcement last Tuesday, US forces in Korea said they had received no guidance on stopping any drills, and South Korean officials said they were trying to figure out which exercises Trump was referring to.

However, in a sign Seoul may be open to suspending drills, South Korean President Moon Jae-in said on Thursday that his government would need to be flexible when it came to applying military pressure on North Korea if it was sincere about denuclearisation.

Mr Moon said South Korea would carefully consider joint military drills with the United States and he asked his officials to cooperate with the United States on the issue, his office said in a statement at the time.

Yonhap also reported on Sunday that during military talks between the two Koreas on Thursday, South Korean officials asked their northern counterparts to relocate artillery 25 miles away from the heavily fortified military demarcation line that divides the two countries.