A top Iranian diplomat said on Friday that the Islamic Republic had agreed with China and Russia that any future talks over Iran's nuclear program must not stray into other issues.
The remarks appear to set a high bar for any new negotiations with United States, which has expressed deep misgivings with Iran's support of armed allies in the Middle East, missile program and domestic dissent.
China and Russia did not immediately confirm the alleged consensus.
"Any future talks must be nuclear talks only," Iran's deputy foreign minister Kazem Gharibabadi said in Beijing, where he was attending a trilateral meeting with Russian and Chinese counterparts.
"We made our position clear and China and Russia take the same position and have always maintained that non-nuclear issues won’t be part of the nuclear talks," he added. "This is the position of all three countries."
The three countries in an earlier joint statement emphasized the need to address the root causes of the nuclear standoff. They condemned unilateral sanctions as illegal and underscored Iran's right to the peaceful use of nuclear energy.
China's foreign ministry on Friday made no mention of the understanding on the scope of talks to which Gharibabadi referred.
"The situation of the Iranian nuclear issue is grim and has once again reached a critical crossroads," it said in a statement.
"China is willing to work with all parties to promote a fair, balanced and sustainable solution to the Iranian nuclear issue, safeguard the international nuclear non-proliferation mechanism, and promote international and regional peace and stability."
US President Donald Trump revealed on Friday that he had sent a letter to Iran's Supreme Leader Ali Khamenei offering negotiations but has warned of military action if talks failed, saying last week the standoff with Tehran was in its "final moments".
Iran's veteran theocrat rejected those overtures again this week, citing Trump's pullout from a 2015 international nuclear deal which involved Russia and China.
In his first term, Trump's administration had cited the deal's alleged leniency on Iran's military activities but the president has more recently repeatedly cited the nuclear program as the sole point of disagreement.
"I really want to see peace ... (but) they cannot have a nuclear weapon", Trump said last month. "It's very simple. I'm not putting restrictions. They cannot have one thing."
Trump, who has taken a hard line on Iran but broadly opposes foreign wars, made the remarks while reimposing harsh sanctions on the country, which were described in official documents as aiming to undermine Iran's broader military activities.
