It remains to be seen how long the truce will hold and whether it will pave the way for a nuclear deal between the U.S. and Iran.

"We have two countries that have been fighting for so long, they don't know what the f-ck they're doing," Trump said.

Separately, in a phone call with the leader of the United Arab Emirates, Sheikh Mohammad bin Zayed, Mr. Pezeshkian signaled a willingness to return to talks, saying Iran was “ready to resolve issues at the negotiating table and within international frameworks,” according to an official readout of the call by the president’s office.