Iran announced Monday that Foreign Minister Hossein Amir-Abdollahian will visit Moscow on Tuesday to discuss the crisis in the negotiations.
The talks face the prospect of collapse after a last-minute Russian demand forced world powers to pause negotiations for an undetermined time despite having a largely completed text.
Also on Monday, Foreign Ministry Spokesperson Saeed Khatibzadeh said that Tehran had warned Iraqi authorities many times that its territory should not be used by third parties to conduct attacks against Iran.
He was speaking one day after Iran attacked Iraq's northern city of Erbil with a dozen ballistic missiles in an unprecedented assault on the capital of the autonomous Iraqi Kurdish region that appeared to target the United States and its allies.
Iran's Revolutionary Guards claimed responsibility for the missile assault.
Iranian state media said the Revolutionary Guards Corps had launched the attack against Israeli "strategic centers" in Erbil, suggesting it was revenge for recent Israeli air strikes that killed Iranian military personnel in Syria.
The Iraqi Kurdish regional government said the attack only targeted civilian residential areas, not sites belonging to foreign countries, and called on the international community to carry out an investigation.