Iran's missile capabilities are a "red line" and will not be a subject of negotiation, said Ali Shamkhani, an adviser to Iran's Supreme Leader, on Wednesday, according to the Reuters news agency.
His remarks came as Tehran and Washington prepare for a new round of talks aimed at preventing further conflict.
Shamkhani's statement, which was reported by state media, came during a march commemorating the 47th anniversary of the Islamic Revolution. "The Islamic Republic's missile capabilities are non-negotiable," Shamkhani declared.
Diplomatic discussions between US and Iranian officials took place last week in Oman, although they were indirect talks.
Following the talks, President Donald Trump described the discussions as “very good" and confirmed that further negotiations are expected.
The Wall Street Journal reported following last week’s talks that Iran rejected US calls to halt its uranium enrichment, although both sides agreed to continue negotiations in order to prevent an escalation.
Iran’s Foreign Minister Abbas Araghchi stated on Sunday that indirect nuclear negotiations with the United States will proceed if Tehran concludes that Washington possesses the “necessary seriousness" to reach a negotiated resolution and has agreed to drop what Araghchi described as the US’ “excessive and unrealistic" demands.