Iran's deputy foreign minister Kazem Gharibabadi warned of a wider escalation if his country was attacked, after US President Donald Trump raised the threat of strikes.
Trump has sent a major deployment of air and sea power to the Middle East and has threatened to strike Iran if it does not reach a deal on key concerns starting with its nuclear program.
"We call upon all nations committed to peace and justice to take meaningful steps to prevent further escalation," Gharibabadi said at the Conference on Disarmament in Geneva.
"The consequences of any renewed aggression wouldn't remain confined to one country -- and responsibility would rest with those who initiate or support such actions."
Iranian and US negotiators held indirect talks in Geneva last week on Tehran's nuclear program, hosted by Oman.
A fresh round of talks in the Swiss city this Thursday has been confirmed by Muscat, though not by Washington.
"Iran remains committed to diplomacy and dialogue as the most effective path towards de-escalation and sustainable security," Gharibabadi said.
"Recent diplomatic engagement here in Geneva, which will continue this Thursday, demonstrates that a new window of opportunity exists for negotiations to address differences and build confidence -- provided that they uphold mutual respect, equitable treatment and non-selective application of international norms.
"Any sustainable and credible negotiation must respect the legitimate rights of all states under international law, and deliver tangible security benefits without coercion, unilateral demands or threats of force."
- 'Chaos and change' -
The United States and Israel threatened new military action against Iran after mass protests in the regime, which the Iranian authorities crushed at a cost of thousands of lives.
After last week's indirect talks with Washington through Omani mediators in Geneva, Tehran said they had reached broad agreement on a set of guiding principles.
Gharibabadi said that while Tehran sought the path of diplomacy, it was prepared to defend its sovereignty, territory and people, insisting it would exercise its right to self-defense "if necessary".
He said meaningful progress in disarmament and non-proliferation could only be achieved through mutual, balanced and legally-binding commitments.
He called upon nuclear weapons states to engage constructively in talks towards a comprehensive nuclear weapons convention, plus offer legally-binding security assurances for countries without nuclear weapons.
Speaking just before, UN Secretary-General Antonio Guterres said the world was living through a period of "chaos and change", with international law being brazenly violated.
"The international order that defined security relations for nearly eight decades is shifting rapidly. The reckless use of force in many regions is fomenting mistrust," he warned.
