U.S. President Donald Trump speaks to the press aboard Air Force One Aug. 2. AFP-Yonhap

WASHINGTON — U.S. President Donald Trump said that negotiations with Iran will begin Monday after he decided to hold off on new "disastrous" strikes against the Islamic republic to pursue a deal.

"Obviously, they don't want to be attacked. They knew the extent of the attack because they saw it forming," Trump told reporters on Sunday aboard Air Force One.

"Now what we're doing is we're talking to them in the form of a negotiation. It begins tomorrow afternoon," he said, without providing further details of the venue of the talks or the participants.

On Saturday, the U.S. president pulled back from threats for a massive attack against Iran which he said would have been the biggest since World War II, saying the "perimeter" of a deal was there.