The economic sanctions on North Korea will remain in place until denuclearisation is achieved, US Secretary of State Mike Pompeo has said. "Those economic sanctions will remain in place until we get to the end, till we get to that final denuclearisation which (North Korean leader) Chairman Kim (Jong-un) promised to (US) President (Donald) Trump he would undertake," Pompeo told MSNBC in an interview on Friday. Pompeo, who has been leading Trump administration's effort with North Korea, plans to travel to Pyongyang soon to work on another meeting between Trump and Kim. "We're working on it, but there's still a little bit of work to do left to make sure that the conditions are right and that the two leaders are put in a position where we can make substantial progress," he told Fox News in another interview. Acknowledging that North Korea has set a deadline of 2021 to denuclearise, Pompeo said in another interview that the US will set arbitrary deadlines in the interim. "We're hoping to see progress a little bit each day. We knew this would be a long process. It's a complicated endeavour. But we've made incremental steps along the way," he said. Describing the meeting between the two Korean leaders as historic, he said it is the first time that North and South Korea have spoken about denuclearisation in a material way. \u201cThey made a little bit of progress. I'm hoping I'll be back in Pyongyang before too long to make some more progress; and if that's the case, I'm very hopeful that Chairman Kim and President Trump will get a chance to meet in the near future as well,\u201d he said. Pompeo said that there are many conversations taking place across many different forums and venues, lots of discussions about how to move forward, and what are the right sets of next steps. "But the end that we can't lose focus on, there are two UN Security Council resolutions that the whole world voted on, and they require the North Koreans to fully denuclearise. That's the mission statement. That's the president's objective. And we believe that we can achieve that before too terribly long," he said. Separately he told CNN that he knew that pace of progress with the North Koreans would be uneven, but that progress each and every day was important. "We think we're getting that," he said as he referred to the UN Security Council- mandated sanctions on North Korea. "The UN Security Council resolutions demand that Chairman Kim make this decision to denuclearise, and those sanctions and the enforcement of those sanctions will continue until such time as that occurs. That's the important element that is different from what previous negotiators have done," he said. "We've always, in America, handed him a pile of money, or his father a pile of money, and said, 'We hope you'll denuclearise'. Our approach is different. It is to continue to enforce the sanctions until such time as we get to the end of the process," Pompeo said.