An Israeli military official told ABC News that Iran fired between 20 and 30 ballistic missiles toward Israel on Sunday morning following the American strikes on three Iranian nuclear sites late on Saturday.

-ABC News' Jordana Miller and Dada Jovanovic

British Prime Minister Keir Starmer and European Union foreign affairs chief Kaja Kallas said in statements to X on Sunday morning that Iran cannot be allowed to create nuclear weapons, while also urging de-escalation and diplomacy to end the spiraling Middle East crisis.

"Iran's nuclear program is a grave threat to international security," Starmer wrote in his statement. "Iran can never be allowed to develop a nuclear weapon and the U.S. has taken action to alleviate that threat."

"The situation in the Middle East remains volatile and stability in the region is a priority," Starmer added. "We call on Iran to return to the negotiating table and reach a diplomatic solution to end this crisis."

Kallas said Iran "must not be allowed to develop a nuclear weapon, as it would be a threat to international security."

"I urge all sides to step back, return to the negotiating table and prevent further escalation," she added.

French Foreign Minister Jean-Noel Barrot, meanwhile, also said Paris "has repeatedly expressed its firm opposition to Iran gaining access to nuclear weapons," though said France reacted to news of the U.S. strikes "with concern." He added, "France was not involved in these strikes, nor in their planning."

"France is convinced that a lasting solution to this issue requires a negotiated solution within the framework of the Non-Proliferation Treaty on nuclear weapons," Barrot added.

-ABC News Dada Jovanovic and Tom Soufi Burridge

At least 19 people were injured by Iranian ballistic missiles fired on Sunday morning, emergency services said. Two people were seriously hurt, one person moderately injured and 16 others sustained minor injuries.

Missiles hit four locations across Israel, including in Tel Aviv where one person was seriously injured.

In the northern port city of Haifa, a missile struck without any warning sirens, prompting concern as to potential problems with the alert system. The Israel Defense Forces said it was investigating the incident.

Israel's Magen David Adom emergency service said one person was seriously injured in Haifa and three others sustained minor injuries.

Elsewhere, five people suffered minor injuries in Nes Ziona while one person was moderately injured in Beer Yaakov, both in central Israel, the MDA said.

-ABC News' Jordana Miller and Dada Jovanovic

The Israel Defense Forces said early Sunday that its forces launched a new wave of strikes in western Iran, which it said included attacks on launchers used to fire ballistic missiles toward Israel shortly before.

"The air force attacked missile launchers in Iran ready to be launched towards the territory of the state of Israel, soldiers in the Iranian military forces and closed the circle and destroyed launchers that had launched towards the territory of the state of Israel a short time ago," it wrote on X.