The incident at Iran's Natanz nuclear facility could be considered as an "act against humanity", Foreign Ministry spokesman Saeed Khatibzadeh told a news conference on Monday.
"There was no contamination or injuries but it could cause a disaster. It could be considered as an act against humanity," Khatibzadeh said.
Iran said the incident at its Natanz nuclear enrichment site on Sunday was caused by an act of "nuclear terrorism".