Flanked by John J. Sullivan, acting secretary of state, left, and Patrick M. Shanahan, deputy secretary of defense, President Trump speaks to the media at the White House on April 9. (Ricky Carioti/The Washington Post)

President Trump expressed optimism Monday about his proposed summit with North Korean leader Kim Jong Un, saying it will take place in late May or early June, the most specific time frame the White House has yet offered.

The president said planning is continuing for the unprecedented meeting, which he said would address North Korea's nuclear weapons. He did not clarify where the session might take place.

“We'll be meeting with them sometime in May or early June,” Trump said at the start of a Cabinet meeting at the White House. “I think there will be great respect paid by both parties and hopefully there will be a deal on denuking.”

“Hopefully it will be a relationship that will be much different than it has been for many, many years,” Trump added. He blamed previous administrations for allowing the relationship with North Korea to get to a crisis point, or failing to negotiate an end to a nuclear program that targets the United States.

“This should have been done by other presidents,” Trump said.

His surprise meeting, announced in dramatic fashion on the White House driveway last month, shocked allies and took some members of his own administration by surprise. At the time, South Korean officials who made the announcement said the summit would take place “by May,” which White House officials later said meant sometime in May. The month is already busy, including a potential Trump visit to Jerusalem for the opening of the U.S. Embassy there. Trump did not elaborate on his slightly adjusted time frame Monday.

The forthcoming summit “will be very exciting for the world,” Trump said Monday.