The US president stressed that it would be "unacceptable" if North Korea does not agree to denuclearize.
"They have to de-nuke. If they don't denuclearize it would not be acceptable. We cannot take sanctions off," Trump said before a working lunch with Japanese Prime Minister Shinzo Abe at the White House.
The US president noted that Washington could sign an agreement to end the Korean war at the meeting with Kim Jong Un, emphasizing that he hoped for normalizing ties with North Korean future.
"I hope the upcoming meeting… represents the beginning of a bright new future for North Korea," Trump stated.
US President Donald Trump said if North Korea summit went well, he would invite Kim Jong-un to the United States.
Trump said he could put more sanctions on North Korea, but decided not to do it at this time and added that his administration can enforce more punitive measures against Pyongyang in the future.
Speaking to reporters as he welcomed Japanese Prime Minister Shinzo Abe to the White House, Trump said he and Abe would discuss trade and issues regarding North Korea.
"The summit is all ready to go. It's going to be much more than a photo op," Trump said, emphasizing that "everything is ready" for the meeting. At the same time, the president once again indicated that everything could still change.
According to the US president, he is "very well" prepared for the summit.
"I don't think I have to prepare very much. It's about attitude," he said.
Last week, Trump announced he was not going to agree to any kind of deal with Kim during their first meeting set for June 12 in Singapore. He underlined that the United States and North Korea were going to "start a process" and a new relationship during the summit.
The long-standing tensions on the Korean Peninsula have significantly de-escalated in 2018 when Kim announced his willingness to denuclearize the country and met with South Korean President Moon Jae In.