WASHINGTON, May 18 (Xinhua) -- U.S. President Donald Trump said Monday a "positive development" is happening and he thought Iran was close to an agreement this time, hours after he announced a postponement of resumption of military strikes against the country.

This time was "a little bit different" from previously stalled talks in which Washington thought a deal was close, Trump told reporters at the White House.

"It's a very positive development, but we'll see whether or not it amounts to anything," he said.

"We've had periods of time where we had, we thought, pretty much getting close to making a deal, and it didn't work out. But this is a little bit different," Trump said.

Trump added that the Gulf states asked him to hold off on attacks against Iran scheduled on Tuesday for a few days, but that the pause could last longer.

Meanwhile, Trump stressed again that it is a must for Iran to give up its nuclear program.

"Now they have to put it down in writing," Trump said. ■