Nuclear program of Iran
Iran reports that a blackout at its underground Natanz nuclear facility is an act of nuclear terrorism and says that they reserve the right to respond, but it does not specify who was responsible or how they would respond. Parts of the electrical grid at Iran's main nuclear facilities at Natanz have been compromised. Intelligence sources claim in Israeli media that the Mossad intelligence agency carried out a cyber attack on the facility.
Sources: Al Jazeera