GEOFF BENNETT: Welcome to the "News Hour."

Tonight, two longtime adversaries in the Middle East are at war.

Massive explosions from an onslaught of Iranian missiles have rocked Israel's largest cities, including Tel Aviv.

AMNA NAWAZ: The U.S. says it's helping to intercept those missiles, which are retaliation for preemptive Israeli strikes that killed top military officers and targeted Iran's nuclear facilities late last night and into today.

That includes a strike on an aboveground facility that led to chemical and radiation contamination.

That's according to the U.N. nuclear watchdog agency.

Both Israel's brazen attack and Iran's unprecedented response have world leaders concerned that the fighting will only escalate.

As night fell in Tel Aviv, the protective Iron Dome system worked to intercept incoming Iranian missiles, hundreds, according to Iran's state-run news agency, launched in revenge, the damage devastating and unlike any Israel had seen in years.

Last night, the sky above Tehran glowed red and buildings below were set ablaze, as Israel carried out a punishing wave of what it called preemptive strikes on military leaders, nuclear facilities and nuclear scientists in Iran, part of an assault Prime Minister Benjamin Netanyahu said was years in the making to prevent a nuclear-armed Iran.

BENJAMIN NETANYAHU, Israeli Prime Minister: Israel launched Operation Rising Lion, a targeted military operation to roll back the Iranian threat to Israel's very survival.

This operation will continue for as many days as it takes to remove this threat.

AMNA NAWAZ: Israeli strikes last night and today hit multiple sites across the country, among them, nuclear targets, several of Iran's main enrichment facilities at Natanz and Fordow.

Ballistic missile sites at Shiraz and Kermanshah were also hit.

Other strikes took out key leaders, including Mohammad Bagheri, the military's commander in chief, and General Hossein Salami, chief of the powerful Islamic Revolutionary Guard Corps.

Tehran deployed a swarm of more than 100 drones overnight, which the IDF says it shot down.

And Iran's supreme leader, Ayatollah Ali Khamenei, warned of severe punishment, a message echoed by Iranian President Masoud Pezeshkian.

MASOUD PEZESHKIAN, Iranian President (through translator): The Iranian nation and its officials will not remain silent in the face of this crime.

The Islamic Republic of Iran's legitimate and powerful response will make the enemy regret its foolish actions.

AMNA NAWAZ: The U.S. response to the strikes evolved over the hours.

In a late-night statement, Secretary of State Marco Rubio said -- quote -- "Israel took unilateral action against Iran.

We are not involved in strikes against Iran."

But, this morning, President Trump told multiple reporters the U.S. knew an Israeli attack was coming, warning in one interview that there is -- quote -- "more to come, a lot more," and in another saying that Iran -- quote -- "should now come to the table to make a deal before it's too late."

In 2018, during Trump's first term, he pulled out of the 2015 Obama era nuclear deal that severely restrained Iran's nuclear fuel enrichment and stockpiles.

In recent months, the Trump White House, led by envoy Steve Witkoff, restarted that effort, holding multiple rounds of talks with Iran to restrict their nuclear program.

Today, after huddling with national security staff in the Situation Room, the president told Axios -- quote -- "Maybe now they will negotiate seriously."

A sixth round of talks was scheduled for this Sunday in Oman.

U.S. forces in the meantime are pivoting in preparation, repositioning military resources in the Middle East, including ships and jets, and ramping up security at regional bases, bracing for what comes next, as two old adversaries begin a new war.