DUBAI/RIYADH — A proposed deal between Iran and Oman to help end five months of war between Iran and the United States would give Tehran control over ships entering the Gulf through the Strait of Hormuz, a senior Iranian source and two regional officials told Reuters on Wednesday, one of the biggest concessions yet to Iran. There was no immediate U.S. comment on the proposal. While President Donald Trump has said a deal reopening the strait is imminent, U.S. officials have repeatedly insisted they would never agree to Iran controlling access to the world's most important trade route for energy supplies. An agreement that gives Iran authority over traffic through the strait would mean the war launched by the United States and Israel in February had resulted in a major shift in the balance of regional power in Tehran's favour. Before the war, the strait was freely open to all ships with no fees. Amid a wider diplomatic effort in the region, Iran and Oman have been engaged in bilateral talks regarding the strait that they each control through northern and southern channels. Iran reported