The United States does not want to see an escalation of the crisis in the Middle East, a top White House official said Sunday after Israel repelled a massive missile and drone attack from Iran.

"We're not looking for a wider war with Iran," White House National Security Council spokesman John Kirby said on NBC's "Meet the Press," adding that the US does not "want to see this escalate."

Israel was on high alert Sunday after Iran's unprecedented attack sparked fears of a broader conflict.

Iran launched its first-ever direct assault on Israeli territory late Saturday in retaliation for a deadly strike by Israeli forces on Tehran's consulate in Damascus on April 1.

It marked a major escalation of the long-running covert war between the regional foes.

The assault saw Iran fire more than 300 drones and missiles toward Israel late Saturday, injuring 12 people, the Israeli army said.

Kirby, speaking also on CNN's "Inside Politics with Manu Raju", said the Pentagon was still counting but that it was "clearly several hundred" drones and missiles.

But almost all were intercepted before they reached Israeli territory, the Israeli army said, with help from the United States, Jordan, Britain and other allies.

The US alone brought down "easily several dozens," Kirby, still speaking on CNN, said.

It was an "incredible effort by Israel," he said, "but also it shows that Iran is not the military power weight that they claim to be."

US President Joe Biden has reaffirmed Washington's "ironclad" support for Israel while appearing to guide its staunch ally away from a military response.

News outlet Axios said the president had told Netanyahu he would oppose an Israeli counterattack against Iran, and that the prime minister should "take the win".

Kirby added in the NBC interview that the United States is "staying vigilant" to any Iranian threats to American troops.

"We made it very clear to all parties, including Iran, what we would do ... and also how seriously we would take any potential threats to our personnel," Kirby said.

Continuing his round of the Sunday morning political talk shows with an appearance on CBS, Kirby elaborated: "We're going to take whatever steps we need to take to protect our troops, our ships, our facilities in the region going forward."

Kirby also stressed that negotiations between Hamas and Israel on a truce in Gaza and a hostage release deal were still underway.

"We're not considering diplomacy dead there," he said.

Kirby said CIA director Bill Burns negotiated a new deal in Cairo about a week ago that would "get dozens of the most at-risk women, elderly, the wounded out, get us a six-week ceasefire."

"The Hamas leaders need to take that deal. And we're not considering this dead at this point."