In a Twitter message on Wednesday, Trump also said the recent meeting between China’s President Xi Jingping and Kim went very well.
“Received message last night from XI JINPING of China that his meeting with KIM JONG UN went very well and that KIM looks forward to his meeting with me,” Trump wrote.
“In the meantime, and unfortunately, maximum sanctions and pressure must be maintained at all cost,” he added.
After several days of speculation, China announced on Wednesday that Kim has met Xi in Beijing, where Kim reportedly made a pledge to dismantle North Korea’s nuclear program.
The trip was Kim’s first known journey abroad since he took over power in 2011.
The White House said on Tuesday that Beijing briefed Trump on the meetings and that the denuclearization pledge was “further evidence that our campaign of maximum pressure is creating the appropriate atmosphere for dialogue with North Korea.”
Earlier this month, Trump unexpectedly agreed to meet Kim but details of potential talks have not been made public. The White House has said they will only happen if North Korea keeps “several promises.”
China, Russia and South Korea have welcomed the possible Trump-Kim summit, which would be the first between a North Korean leader and a sitting US president.
Tensions were running high between Washington and Pyongyang over North Korea's missile and nuclear programs.
Trump and Kim have repeatedly traded insults and threats of military attacks that raised fears of a war between Pyongyang and Washington in recent months.