A powerful explosion rocked Tehran on Sunday as the Israeli military said it was targeting the “heart” of the city. The blast sent a towering plume of smoke into the sky and shook surrounding neighborhoods, according to AP.

It was not immediately clear what specific site had been struck. The explosion appeared centered in an area housing Iran’s police headquarters and facilities linked to state television.

Israel said it was striking key targets in central Tehran after clearing what it described as a path to the capital a day earlier. The attack marks a sharp escalation in hostilities between Israel and Iran, AP reported.