Iran launched multiple deadly waves of missiles and drones toward Israel into Saturday morning following Israel’s unprecedented strikes aimed at destroying Iran’s nuclear program and decapitating its military leadership.

Tehran said American bases in the Middle East could face reprisals if the U.S. helped repel Iranian attacks on Israel.

Israel’s ongoing attacks on Iranian nuclear sites, generals, and scientists killed 78 people and wounded more than 320 on Friday, Iran’s ambassador told the U.N. Security Council, but he said “the overwhelming majority” of victims were civilians. Israel described the new wave of hostilities as the beginning of “Operation Rising Lion.”

Airlines around the world canceled flights to Israel and were skirting a large swath of airspace in the Middle East on Friday after Israel’s overnight missile strikes on Iran.

The two sides were due to meet for a sixth round of negotiations on Sunday. Tehran suggested that it had not yet decided whether to participate, given Israel’s attack on its nuclear infrastructure.

Air raid sirens have sounded across Israel and interceptions were visible overhead in Tel Aviv following an Iranian missile attack on the country.