Global shares rallied and the dollar extended declines on Tuesday after U.S. President Donald Trump said Iran and Israel had agreed to a ceasefire, sending oil prices into a deep dive as concerns over supply disruptions ebbed.

Trump signaled Monday that he’s wary of rising oil prices that spiked Sunday after the U.S. military attacked nuclear sites in Iran. Prices had dropped again Monday. And with Americans heading into the busy Fourth of July driving season, the president sought to publicly address concerns that soaring gasoline prices might follow.

Oil prices may change after the United States’ involvement in the Israel-Iran war. Some experts warn that possible retaliation by Iran could interrupt the influx of crude oil, which may harm global economies.