Israel’s attack on Iran was long in the making – the result of years of meticulous planning by Israel and days of high-stakes talks between Tel Aviv and Washington, officials told CNN.

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.”

Amidst the new Iran Israel conflict, Greece is concerned about the safety of Greek citizens and the impact on maritime safety and tourism.

Republicans and some Democrats offered strong support for Israel’s move, but many Democrats called for de-escalation and warned of the consequences of a broader war.

Israel launched “preemptive” strikes early Friday across Iran, amid growing regional tensions and concerns about Iran’s nuclear capabilities.

In all, at least 20 senior commanders were killed, two regional sources said. The head of the Revolutionary Guards aerospace force was also reported to be among them.