Singapore, Jun 12 (IANS): The US will end its joint military exercises with South Korea, but sanctions on Pyongyang will remain in place, President Donald Trump announced on Tuesday.

Trump's statement came after he signed an agreement with North Korean leader Kim Jong-un which included a pledge to work towards a "complete denuclearization of the Korean Peninsula".

The US leader said he believed his North Korean counterpart would live up to the agreement. But "in the meantime the sanctions will remain in effect".

He said he would push for North Korea to denuclearize as "fast as it can mechanically" but added it could take a long time. "Scientifically you have to wait certain periods of time... But once you start the process, it means it's pretty much over."

Trump said the process would start "very soon" and added sanctions would be removed "when we are sure the nukes are no longer a factor".

He also said he would stop the joint military exercises with South Korea, which North Korea describes as a "preparation for war". The President also described the military exercises as "too expensive".

Trump said he hopes to eventually withdraw US forces from South Korea, but said "that's not part of the equation right now.

"I want to get our soldiers out. I want to bring our soldiers back home... But that's not part of the equation right now. I hope it will be eventually."

Trump said he had agreed to stop the "war games" because he considers them "very provocative" and said it would save the US "a tremendous amount of money".

"We've done exercises for a long period of time, working with South Korea... They're tremendously expensive. South Korea contributes but not 100 per cent. We have to talk to many countries about treating us fairly. The war games are very expensive, we pay for a big majority of them."

He added: "We're negotiating a very complicated deal... I think it's inappropriate to have war games."

Trump said the summit marked a "great moment in the history of the world" and stressed that denuclearization would be verifiable by international and US experts.

The leaders have agreed to have follow-on negotiations led by US Secretary of State Mike Pompeo and a senior North Korean official.

Trump said he had invited Kim to visit the White House at "the appropriate time" and that the North Korean leader had accepted his invitation.

He said that Kim told him that North Korea was "destroying a major missile engine testing site". The commitment was not included in the joint declaration the two men signed, but Trump said: "We agreed to that after the agreement was signed."

Trump said he was confident that Kim will live up to the document that they both signed. "I don't think they have ever had the confidence in a President they have right now for getting things done."

He also praised Kim "ability to run a country at a young age". "He is very talented," Trump said.

Asked about a possible second summit with Kim, Trump told reporters that while one hasn't been set up yet. "We'll probably need another summit or meeting."