An aggressive counterattack risks escalation. But giving in to U.S. and Israeli demands is an unlikely alternative.

Israel targeted nuclear and military sites in Iran in airstrikes early Friday morning.The strikes are a major escalation that threatens to expand into a wider regional conflict.These are five key questions in the wake of Israel's air war.

The U.S. was represented at the UN Security Council's emergency session on Friday by State Department Senior Bureau Official McCoy Pitt, who said the U.S. was advised by Israel that the actions carried out against Iran overnight were "necessary for its self-defense."

In response to Israel’s attack, Iran fired back with more than 100 drones. NBC News’ Chief International Correspondent Keir Simmons reports more. Former NATO Supreme Allied Commander retired Gen. Wesley Clark and Senior Fellow at the Carnegie Endowment for International Peace Aaron David Miller join Ana Cabrera to examine the possibility of further attacks.

Iran began its retaliation campaign early Friday, after warning Israel it would pay a “heavy price” for its attack.

Sirens sounded in Israel as the Israel's military said Iran launched ballistic missiles and more than 100 drones in what appeared to be the start of Iranian retaliation for Israeli strikes on its nuclear facilities.

A United Nations conference co-hosted by France and Saudi Arabia aimed at forging a roadmap towards a two-state solution between Israel and the Palestinians has been postponed after Israel launched a military attack on Iran,