In a phone call with Egypt's top diplomat Badr Abdelatty, Araghchi said "success in this path requires seriousness and realism from the other side and avoidance of any miscalculation and excessive demands."

Araghchi did not clarify what demands he was referring to, but Washington has pointed to Iran's ballistic missile programme and has repeatedly described Tehran's uranium enrichment capability as a red line.

US President Donald Trump said on Wednesday that Tehran had "already developed missiles that can threaten Europe and our bases overseas, and they're working to build missiles that will soon reach the United States of America".

Also on Wednesday, US Secretary of State Marco Rubio said Iran is "not enriching right now, but they're trying to get to the point where they ultimately can", adding that Tehran "refuses" to discuss its ballistic missile programme and "that's a big problem".

Iran has repeatedly said its missile programme is part of its defensive capabilities and has ruled out abandoning uranium enrichment, insisting its nuclear programme is solely for peaceful purposes.

Longtime adversaries Iran and the United States held their third round of Omani-mediated nuclear talks on Thursday in Geneva, seeking to avert military escalation as Washington expands its military build-up in the region.

Both Iran and Oman cited progress after the talks, with technical discussions scheduled for Monday in Vienna ahead of a fourth round expected next week.