US President Donald Trump warned Sunday that Iran could face a decisive military blow if the conflict continued, saying his desire to avoid further loss of life was the only reason the United States had not already brought the war to an end.

Speaking at a campaign rally in Iowa ahead of Tuesday's midterm elections, Trump said, "The only reason we are not finished with Iran is because I want to be nice. I want to try and save all those lives if I can. But at some point, we're going to have to give them the hammer."

The President also predicted that the conflict would conclude shortly, although he did not provide a specific timetable.

“It’s going to be over very soon. Very soon."

Addressing the economic consequences of the war, Trump defended the increase in oil prices as a necessary cost of protecting the United States and the international community.

He said he had anticipated a significantly larger increase in energy prices and predicted that oil would become substantially cheaper once the fighting ended.

“When that war is over, it’s going to come plunging," Trump said. “It’s a very small price to pay for the security of this country and for the world."

Trump also reiterated his assertion that the American military campaign had prevented Iran from acquiring nuclear weapons.

Earlier Sunday, speaking to RSBN before the Iowa rally, Trump indicated that Washington would bring the confrontation to a conclusion through either diplomacy or additional military action.

"We've had such a victory and we'll put it away very soon, one way or the other. Either they'll make a deal or we'll just end it, end it the, I guess you could say, maybe the easy way," he said.

The President had expressed cautious optimism about diplomatic efforts during remarks to reporters Saturday night, describing negotiations with Iran as "going fine" and saying he was not "in much of a hurry" to reach an agreement.

However, he questioned Tehran's reliability, saying the Iranians "are not very reliable. ... They make a deal, and then they back out."

Trump also identified additional Iranian nuclear facilities as potential targets, including the suspected underground installation known as Pickaxe Mountain.

"We can do that in 10 minutes. We have that planned. You can look at Pickaxe Mountain. We need to take care of that. We can do that very quickly," he warned.

Meanwhile, indirect negotiations between Washington and Tehran continued under Qatari mediation.

Reports on Saturday indicated that preliminary understandings had been reached concerning Iran's nuclear program, maritime traffic through the Strait of Hormuz and possible economic incentives for Tehran.

An American delegation was also reportedly expected to meet Iranian representatives in Doha as diplomatic efforts continued.