Negotiations between Iran and the US can only bring harm, Iran's Supreme Leader Ayatollah Khamenei said on Wednesday – as US allies gather in Warsaw for a meeting on the Middle East.
The remarks were part of a seven-page statement read out loud on Iranian state television, the Associated Press reported.
The Supreme Leader said, "about the United States, the resolution of any issues is not imaginable and negotiations with it will bring nothing but material and spiritual harm."
Tensions between the US and Iran are high following the US withdrawal from the Joint Comprehensive Plan of Action – otherwise known as the nuclear deal – last year, and increasing Iranian interference in conflicts in the Middle East.
The summit in Warsaw was announced by US Secretary of State Mike Pompeo during an eight-day tour of the Middle East.
Some 60 countries gathered in Poland's capital to discuss issues relating to the Middle East – principally Iran.
Iran's Foreign Minister Mohammad Javad Zarif said that the meeting was "dead on arrival" at a press conference on Wednesday.
"It is another attempt by the United States to pursue an obsession with Iran that is not well-founded," Mr Zarif told a Tehran news conference.
"The Warsaw conference I believe is dead on arrival."