The president said if Iran continued to "threaten" the United States, the country would face "consequences the likes of which few throughout history have ever suffered before".
The message echoed remarks Trump made to North Korean dictator Kim Jong-un in August a year ago amid a flurry of missile tests. "In light of these protests and 40 years of regime tyranny, I have a message for the people of Iran: The United States hears you", he said.
However, during his weekly cabinet meeting Monday, Israeli Prime Minister Benjamin Netanyahu also praised the president's statements regarding Iran.
President Donald Trump warned Iranian President Hassan Rouhani late Sunday of "CONSEQUENCES THE LIKES OF WHICH FEW THROUGHOUT HISTORY HAVE EVER SUFFERED BEFORE" after the Iranian leader said a US-Iran conflict would be the "mother of all wars".
Trump's administration regards Iran as a risky influence int he Middle East amid tensions rising tensions over Syria and its involvement with the war in Yemen. The United States supports you.
Addressing his United States counterpart Donald Trump, Rouhani said: "You declare war and then you speak of wanting to support the Iranian people".
Iranian Supreme Leader Ayatollah Ali Khamenei on July 21 backed Rohani's suggestion and said that "if Iran's oil is not exported, no regional country's oil will be exported".
"Iran is not the same country anymore, that I can say", Trump said at the Veterans of Foreign Wars National Convention in Kansas City, Mo.
The gathering was the first time a top U.S. official had directly addressed such a large number of Iranian Americans, says BBC state department correspondent Barbara Plett Usher.
Trump's comments came after Pompeo, in a major address to the Iranian diaspora in California, said Washington was not afraid to sanction top-ranking leaders of the "nightmare" Iranian regime.
Wicker, who sits on the Senate Armed Services Committee, opposed the controversial Iranian deal under the Obama administration and supported Trump for withdrawing from it in May.
A prominent Lebanese analyst says he is concerned the latest harsh words exchanged by the USA and Iranian presidents have brought the two countries to the brink of war.