"My message is simple and clear: stop escalation. Exercise maximum restraint. Restart dialogue," UN Secretary-General António Guterres said.
"It is clear to us that Iran bears responsibility for this attack. There is no other plausible explanation," Britain, France and Germany said.
Iran will return to nuclear deal only if the US accepts a €14 bn oil credit line proposed by France.
Iranian state media has quoted Foreign Minister Mohammad Javad Zarif as confirming that the limit had been breached.