Iran answered threats of Israel and the United States for "unconditional surrender" by firing hypersonic missiles into Israeli cities on the sixth day of conflict, but damage inflicted by Israeli airstrikes to Iran's nuclear facilities surfaced more clearly.

US President Donald Trump, calling for Iran's compliance for a deal, issued on Tuesday the warning against Iran's Supreme Leader Ali Khamenei on Truth Social platform: "We know exactly where the supreme leader is hiding," he wrote. "We are not going to take him out (kill!), at least not for now ... Our patience is wearing thin."

Three minutes later he posted, "Unconditional surrender!"

Early Wednesday saw an English answer from Khamenei on X platform: "We must give a strong response to the terrorist Zionist regime. We will show the Zionists no mercy." In central Teheran, protesters gathered to denounce Trump's recent comments on their leader.

Ali Bahreini, Iran's ambassador to the United Nations in Geneva, told reporters that he saw the US as "complicit in what Israel is doing", and Iran will respond firmly to the US if it becomes directly involved in Israel's military campaign.

Despite concerns of the international atomic energy community over nuclear safety, Israel's military said on Wednesday that "more than 50 fighter jets" struck an Iranian centrifuge production facility and multiple weapons manufacturing sites, as it now "has control of Iranian airspace" and intends to escalate the campaign in coming days.

Israeli Prime Minister Benjamin Netanyahu claimed earlier that Israeli strikes on Iran's nuclear sites have set the country's nuclear program back a "very, very long time". Iranian media reported several explosions on Tuesday in the central city of Isfahan, home to nuclear facilities.

For the first time in days, the International Atomic Energy Agency or IAEA said on Tuesday that an Israeli strike directly hit the underground enrichment halls at the Natanz facility, revising an earlier assessment after initially reporting it had been hit only indirectly.

IAEA also said two centrifuge production facilities in Iran, a workshop in Karaj and the Tehran Nuclear Research Center were also hit in Israeli attacks.

Celebrating in social media that "A tornado sweeps through Tehran", Israeli Defense Minister Israel Katz, has vowed to take out all nuclear sites of Iran, especially facilities at Fordow, which is built deep into a mountainside and reportedly not easy for Israeli strikes.

In comments to German media at the G7 summit in Canada, German Chancellor Friedrich Merz said it was "dirty work Israel is doing for all of us" by carrying out strikes on Iran's nuclear sites, Deutsche Welle reported on Tuesday.

Iran maintains its nuclear program is peaceful. US Director of National Intelligence Tulsi Gabbard has testified to Congress that Iran was not building a nuclear weapon, and that Iranian supreme leader had not reauthorized the dormant program, AP reported. But during an overnight flight back to Washington from the G7 summit, dismissed the chief of spy agencies. "I don't care what she said," Trump told reporters on board Air Force One.

In retaliation, Iran told residents of Tel Aviv and Haifa to prepare for attacks, with the Islamic Revolutionary Guard Corps claiming its hypersonic Fattah-1 missiles were "repeatedly shaking the shelters" in Tel Aviv.

Hypersonic missiles travel at more than five times the speed of sound and can maneuver mid-flight, making them harder to track and intercept. The Wall Street Journal reported on Wednesday that Israel was running low on defensive "Arrow" missile interceptors, citing an unnamed US official.

Mohamed El Baradei, former IAEA chief during 1997-2009, said on X that Israeli attacks on Iranian nuclear facilities and Trump's threat of "total surrender" were "a clear act of national humiliation".

The assault on Iran "is a sure way to destroy" the Treaty on the Non-Proliferation of Nuclear Weapons, he warned, adding that it "sends a clear message to many countries that their ultimate security is to develop nuclear weapons".

Sarah Leah Whitson, a US-based lawyer, warned that assassinating Iran's supreme leader could be a violation of international law and "continued belligerence and hostile rhetoric" by Trump is "only throwing fuel on the fire".

As the US is deploying more fighter jets to the Middle East, Trump and his team were considering a few options, including joining Israeli strikes on Iranian nuclear sites, three US officials told Reuters.

A YouGov poll showed most US people believe the US military should not get involved in the Israel-Iran conflict, with some 60 percent opposing the move and only 16 percent supporting it.

Despite international alarm, neither side has backed off from the long-range blitz that began on Friday, when Israel's unprecedented attacks targeted Iranian nuclear and military facilities.

Due to the deadly strikes, foreign governments have started to evacuate their citizens.

Agencies contributed to this story.