The president also said Israel and Iran have been fighting for so long that they "don't know what the f*** they're doing."

President Donald Trump on Monday announced that Israel and Iran had agreed to a ceasefire, after more than a week of fighting following Israel's strikes -- and subsequent U.S. attacks -- on Iran's nuclear program.

President Trump spoke by phone with Israeli Prime Minister Benjamin Netanyahu on Tuesday morning to lay out his concerns about the fragility of the cease-fire with Iran, according to a White House official.