The European External Action Service posted a statement on its website, denouncing the assassination.
“This is a criminal act and runs counter to the principle of respect for human rights the EU stands for,” said the statement, attributed to an EEAS spokesperson.
“In these uncertain times, it is more important than ever for all parties to remain calm and exercise maximum restraint in order to avoid escalation which cannot be in anyone’s interest.”
High-ranking Iranian nuclear physicist Mohsen Fakhrizadeh was assassinated in an roadside ambush near Tehran on Friday.
State TV confirmed the killing a short time later, and Foreign Minister Javad Zarif quickly alleged that Israel was involved.
“Terrorists murdered an eminent Iranian scientist today,” Zarif tweeted. “This cowardice — with serious indications of Israeli role — shows desperate warmongering of perpetrators.”
Syria also accused Israel of involvement, with Foreign Minister Faisal Mekdad claiming the act would fuel tensions in the region.
Israel responded only with a statement from the minister for Settlement Affairs, Tzachi Hanegbi, saying he had “no clue” who was behind the killing, according to Al Jazeera.