Iranian Foreign Minister Abbas Araghchi says Tehran has not received a letter from US President Donald Trump.
"We have also heard of it (the letter) but we haven't received anything," Araghchi told reporters on Saturday.
He added that Iran has never and will never agree to negotiations that imply coercion.
The top Iranian diplomat made the remarks after the US president claimed on Friday that he has sent a letter to Leader of the Islamic Revolution Ayatollah Seyyed Ali Khamenei and proposed to negotiate with Iran on a deal on the country's nuclear program.
"I said I hope you're going to negotiate, because it's going to be a lot better for Iran," Trump claimed, before threatening Tehran with military action.
Trump’s claim was immediately dismissed by Iran's permanent mission to the United Nations which said, “We have not received such a letter yet.”
On Saturday, Ayatollah Khamenei said the insistence of some bullying powers on holding talks with Iran does not aim to solve issues but rather aims to assert and impose their own expectations.
“Absolutely, the Islamic Republic will not accept their expectations,” Ayatollah Khamenei added.
In May 2018, Trump pulled Washington out of a multilateral international agreement, formally known as the Joint Comprehensive Plan of Action (JCPOA), signed between Iran and the five permanent members of the United Nations Security Council plus Germany in 2015.
The UNSC-endorsed agreement required Iran to scale back some of its nuclear activities in return for the lifting of cruel sanctions imposed on the country, especially by the United States.
Trump then imposed severe economic sanctions against Tehran while Iran was adhering to its commitments under the deal and even continued to do so for a year after the US withdrawal.
Tehran started to reduce its commitments under the JCPOA in a series of pre-announced and clear steps after witnessing the other parties' failure to secure its interests under the agreement.