The emergency situation that took place at Natanz nuclear facility on Sunday shut off the systems of uranium enrichment. This made the government suspend the production process. The New York Times reported that citing the source in the U.S. intelligence.
"Two intelligence officials briefed on the damage said it had been caused by a large explosion that completely destroyed the independent — and heavily protected — internal power system that supplies the underground centrifuges that enrich uranium. The officials, who spoke on the condition of anonymity to describe a classified Israeli operation, said that the explosion had dealt a severe blow to Iran’s ability to enrich uranium and that it could take at least nine months to restore Natanz’s production", reads the story.
The Iranian government called the incident an act of sabotage perpetrated by Israel. Tehran did not specify what actually caused the power shutdown on the protected facility. Israel publicly refused to confirm or deny any responsibility for the emergency.
The incident occurrred on April 11. Initially, the Iranian government considered it a terrorist act. The emergency took place the next day after Iran lauched the new centifuges designed to enrich uranium.