U.S. markets were poised to open with gains and oil prices fell sharply Monday after President Donald Trump said he would order U.S. forces to refrain from attacks against Iran and that a deal to end the fighting was near.

Futures for the S&P rose 0.6%, while futures for the Dow Jones Industrial Average climbed 1.1%. Nasdaq futures were up 0.3% before the opening bell Monday.

In Asia, Japan’s Nikkei 225 index lost 0.9% and the U.S. dollar dipped against the yen after the U.S. and Japan confirmed they had acted to prop up the value of the Japanese yen against the dollar.

The retreat in oil prices Monday was just the latest of many big swings since the U.S. and Israel attacked Iran in late February. On-and-off fighting and comments from Trump about which way the conflict was heading have been the major drivers of rising and falling oil prices.

Just a day before Trump said he would order the military to pull back on the aggression, the president said he was “losing faith” in the negotiations with Iran, warning that the U.S. military “will be hitting them very hard.”