The above-ground pilot enrichment plant at Iran's Natanz nuclear site has been destroyed, U.N. nuclear watchdog chief Rafael Grossi told a meeting of the U.N. Security Council on Friday on Israel's strikes on Iran.

Israeli defense officials believe damage to major facility is significant, while other enrichment facility at Fordo, nuclear sites in Isfahan, Busheir reportedly not targeted

Israel was seeking to destroy the beating heart of the Iranian nuclear program. The Natanz facility is where Iran has produced the vast majority of its nuclear fuel — and, in the past three years, much of the near-bomb-grade fuel that has put the country on the threshold of building nuclear weapons.