Iran accuses Israel of sabotaging nuclear site, vows revenge 04:09 Tehran (CNN)Iran's Foreign Minister Javad Zarif has vowed revenge against Israel after an apparent attack on an Iranian nuclear site caused a blackout at the facility over the weekend. The incident threatens to undermine recently revived diplomatic efforts between Washington and Tehran to revive the 2015 nuclear deal. Newly inaugurated centrifuges at Iran's Natanz facility, a centerpiece of the country's contentious nuclear program, appeared to have been badly damaged in Sunday's incident, which Tehran has described as an act of "nuclear terrorism." Israel's army chief hinted at possible Israeli involvement in the attack in comments on Sunday. Several Israeli media outlets, quoting unnamed intelligence sources, said Mossad, the national intelligence agency, was behind the operation but offered no other details.