US President Donald Trump has threatened to bomb Iran if it continues to develop its nuclear program.

In an interview with an NBC reporter late Saturday, Trump said, "If they (the Iranians) don't make a deal, there will be bombing," also threatening to punish Iran by imposing what he called "secondary tariffs."

Separately, Trump said he was "very angry" with Russian President Vladimir Putin over the war in Ukraine, threatening to impose new tariffs on Russian oil in an interview with NBC on Sunday.

Trump, who announced he plans to speak with Putin next week, warned that "if Russia and I cannot reach an agreement to stop the bloodshed in Ukraine, and I believe that was Russia's fault, I will impose secondary tariffs on oil coming out of Russia."