"There has been no official attribution and there are several accusations that we are aware of, but it has to be clarified what happened and who is behind it," European External Action Service (EAS) spokesman Peter Stano said, adding that the incident could have been an act of sabotage.
The power outage occurred in an area of the Natanz power distribution network, a plant of about 100,000 square meters that was built eight meters underground to prevent attacks.
Iran blamed the sabotage on Israel, a country that wants to limit Persian nuclear capacity and hinder negotiations to revitalize the Joint Comprehensive Plan of Action (JCPOA).
Stano said that any attempt to derail the diplomatic negotiations underway in Vienna to salvage this nuclear deal must be completely rejected.
"All issues concerning the nuclear program have to be resolved by diplomatic means because there is no other sustainable alternative," he stressed.
Meanwhile, Israel's Prime Minister Benjamin Netanyahu on Monday said he will never allow "Iran to obtain nuclear weapons". This statement was made during a joint press conference with U.S. Defense Secretary Gen. Lloyd Austin, who is on an official visit to Israel.
For lack of progress in the Vienna talks to rescue the Iran Nuclear Agreement, Tehran keeps its word: the Uranium enrichment program will continue until the US is forced to eliminate all sanctions against the Persian state. pic.twitter.com/QdPTsdsSg5