

— If they don't make a deal, there's gonna be a bombing. It will be a bombardment that has never been seen before," said Trump in a telephone conversation reported by NBC writer Kristin Welker, referring to his bid to negociate an Iranian atomic program.
The U.S. president besides threatened Iran with "secondary duties", i.e. the imposition of duties on Iran's oil merchant countries.
Iran rejects Donald Trump's proposals
Iran rejected direct negotiations with the United States on its atomic programme “On Sunday, Iranian president Masud Pezeshkan stated in consequence to U.S. president Donald Trump’s letter on the matter.
Pešekan pointed out that Iran's response, transmitted through Oman, leaves open the anticipation of indirect talks with Washington. However, specified talks have not led to any advancement since Trump unilaterally withdrew from the 2015 atomic agreement between Iran and planet powers during his first word in 2018.
— We do not avoid talking; so far the problem for us is breaking promises. (Americans) gotta prove that they can build trust,” said Pezeshkan at a government meeting.
Last Sunday Iran's abroad Minister Abbas Aragchi reported that his country "does not oppose" talks with the United States. However, he made it clear that negotiations would not be possible until Washington changed its approach to Tehran.
In mid-March Trump sent a letter to the Iranian authorities proposing negotiations on a fresh atomic agreement. It was intended to give the Iranian authorities 2 months to make a decision and endanger to exacerbate the sanctions that Trump imposed on Iran in early February as part of the "maximum pressure" campaign.
The 2015 agreement softened global sanctions in exchange for Iran's atomic programme simplification and allowed abroad inspectors to access Iranian atomic facilities.