Iran said Wednesday that exchanges of messages with the United States are continuing through mediators based on Tehran's 14-point proposal, while accusing Washington of seeking to reignite conflict in the Middle East through military threats.

Mohammad Bagher Ghalibaf, who warned of a "forceful response," was speaking after Iran's Revolutionary Guards said any renewed war would spread far beyond the Middle East.

"The enemy's movements, both overt and clandestine, show that despite economic and political pressure, it has not abandoned its military objectives and is seeking to start a new war," Ghalibaf said in an audio message carried by Iranian media.

Trump, however, left the door open to diplomacy on Wednesday, telling reporters the United States was in the "final stages" of negotiations with Iran.

"We'll either have a deal or we're going to do some things that are a little bit nasty. But hopefully that won't happen," he said.