United States President, Donald Trump and his North Korean counterpart, Kim Jong Un on Tuesday signed what he described as a “pretty comprehensive” document to cap off their historic summit in Singapore.

Trump and Kim sat beside one another at a large wooden table in front of a bank of US and North Korean flags to endorse the document, the specific contents of which still remain unknown.

“I think both sides are going to be impressed with the result. We’re going to take care of a very big and very dangerous problem for the world,” Trump told reporters after the meeting.

While noting that more details about the document would be released to the public in due course, Trump said he would absolutely invite Kim to the White House to continue their “historic” talks.

“We had a historic meeting and decided to leave the past behind, and we are about to sign a historic document. The world will see a major change,” Kim told reporters through an interpreter.

The ceremony concluded a ground-breaking summit which appeared impossible just about one year ago when verbal threats from both leaders against each other fueled growing nuclear crisis.

Trump had mocked the North Korean leader as a “Little Rocket Man” as the two exchanged barbs over their weapons programs. Kim responded by dismissing the president as a “mentally deranged dotard” who would “pay dearly” for his threats against Pyongyang.

Trump and Kim, however, appeared to have a friendly rapport during their day together at the Singapore island resort.

The pair shook hands and met in a one-on-one setting before conferring with aides. The president even showed the North Korean leader the inside of his limousine after their sessions were over.

Despite the optimistic rhetoric, the summit did not appear to produce an iron-clad denuclearization agreement or a peace treaty to end the Korean War -two possibilities Trump raised ahead of the talks.