Israel and Iran have begun a new round of attacks, as the conflict between the two heavily armed rivals enters its fourth day.

"American Forces are maintaining their defensive posture & that has not changed," the chief Pentagon spokesperson said.

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 bombing of Iranian targets ignites political clash as Democrats, Republicans, and media figures debate Netanyahu's actions and Trump's Middle East influence

President Trump is trapped between the “America First” isolationists and others in his party who are cheering on Israel’s strikes against Iran.

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.

“They should now come to the table to make a deal before it’s too late. It will be too late for them. You know the people I was dealing with are dead, the hardliners,” he added. The strikes killed the head of Iran's Revolutionary Guard Corps, and the country's top two military officials, in addition to several nuclear scientists.

Iran has launched a new wave of missile attacks on Israel, triggering air raid sirens across the country as emergency services reported at least three killed and dozens more wounded in the fourth day