WASHINGTON:- President Trumpinfo-icon threatened Iraninfo-icon late Sunday, warning of severe "consequences," as rhetoric between the two countries' presidents escalated dramatically.

Mr. Trump, in an all-caps message on Twitterinfo-icon addressed to President Hassan Rouhani of Iran, wrote that the country would face "CONSEQUENCES THE LIKES OF WHICH FEW THROUGHOUT HISTORYinfo-icon HAVE EVER SUFFERED" if he continued to threaten the United Statesinfo-icon.

Mr. Trump's message was apparently in response to a speech on Sunday by Mr. Rouhani, who warned the United States that any conflictinfo-icon with Iran would be the "mother of all wars."

Mr. Rouhani had earlier threatened the possible disruption of regional oilinfo-icon shipments if its own exports were blocked by United States sanctions.

On Saturday, Iran's supreme leader, Ayatollah Ali Khamenei, said he supported Mr. Rouhani's suggestion, an indication that Iran's leadership was in accord over the apparent threat. Mr. Rouhani has long been considered a more pragmatic leader who was seen as tolerable to moderates.

Mr. Trump announced in May that the United States was withdrawing from the 2015 Iran nuclear deal, and last month the United States said it would impose sanctions on all exporters of Iranian oil. American officials have since moderated the sanctions demand, which roiled oil markets.

Mr. Trump's emphatic tweet about Iran, with its reminders of the enormous military power the United States projects in the Persian Gulfinfo-icon, had echoes of his treatment of North Koreainfo-icon last summer. He would often denounce the regime as corrupt. In the president's mind, these threats destabilized the North and forced it into negotiations over its nuclear weaponsinfo-icon and missileinfo-icon programs.

Iran is both an easier case and a harder one than North Korea. There are no signs that it possesses nuclear weapons now or could in the near future. It has not made any move to pull out of the 2015 deal, even after the United States did. Its leaders appear convinced that Mr. Trump is trying to goad them into making a mistake.

Mr. Trump's warning to Iran came hours after a speech by Secretary of State Mike Pompeo that was harshly critical of Iran's leadership. Mr. Pompeo accused Iran's leadership of widespread corruptioninfo-icon at the expense of its citizens' welfare.

"Governments around the worldinfo-icon worry that confronting the Islamic Republic harms the cause of moderates, but these so-called moderates within the regime are still violent Islamic revolutionaries with an anti-Americainfo-icon, anti-West agenda," Mr. Pompeo said in the speech at the Ronald Reagan Presidential Library in Simi Valley, Calif. "You only have to take their own words for it."

Mr. Trump's tough talk with Iran comes as he continues to face fierce criticism over his meeting last week with President Vladimir V. Putin of Russiainfo-icon and vacillating statements over whether he believes Russia interfered in the 2016 election.

This week Paul Manafort, Mr. Trump's former campaign manager, is scheduled to face trial in Alexandria, Va., on charges of financial improprieties, the first of two criminal trials he faces. The trial will be the first prosecuted by the special counsel, Robert Mueller, who is investigating Russia's interference in the presidential election.