Israel carried out a retaliatory strike against Iran Friday in the early morning hours.

Unnamed Israeli defense officials, as well as a number of Iranian officials, confirmed the strike on Iran. Iranian officials claim that Israel used small exploding drones to carry out the attack—drones potentially launched within Iran’s borders. The strike, Israel’s first action against Iran since the Iranian attack last weekend, reportedly hit an Iranian military base in Isfahan, the city where Iran does a large amount of its missile development and production.

After Iran launched a strike against Israel over the weekend in response to a prior Israeli strike on an Iranian diplomatic installation in Damascus, Iranian officials claimed that they viewed the matter as concluded. Nevertheless, Iran’s President Ebrahim Raisi promised that “the tiniest act of aggression” against Iran in the future would provoke a response. Yet both Israel’s strike and Iran's reaction to it have been much more tempered than many expected.

While the Biden administration has admitted Israel tipped off the U.S. moments before the strike, Secretary of State Antony Blinken said America “has not been involved in any offensive operations.”