Iran’s supreme leader Ayatollah Ali Khamenei was killed in a major airstrike in downtown Tehran, Iranian state media reported early Sunday, a development President Donald Trump said hours earlier would give Iranians a “greatest chance” to “take back” their country.

State media said the 86-year-old was killed in an airstrike targeting his compound in central Tehran, and Iranian TV said his death at his office “showed that he consistently stood among the people and at the forefront of his responsibilities,” while confronting what officials called “global arrogance.” Satellite photos analyzed by AP showed the site was heavily bombed.

Trump, in a statement and a social media post, said the operation would be followed by “heavy and pinpoint bombing” and warned that it would continue throughout the week and even beyond. In the social media post, he wrote, “Khamenei, one of the most evil people in History, is dead,” and he said it gave Iranians “the single greatest chance” to “take back” their country.

Iran said it would respond. The Cabinet called the killing a “great crime will never go unanswered,” and the paramilitary Revolutionary Guard threatened its “most intense offensive operation” ever targeting Israeli and American bases, as Iran moved to organize leadership in the wake of Khamenei’s death.

Because Khamenei had final say on major policies during decades in power and there was no known successor, the killing appeared likely to create a leadership vacuum, with Iran quickly forming a council to govern until a new supreme leader is chosen.

The strike unfolded as the United States and Israel carried out a joint operation described as planned for months. AP reported the attack began Saturday during the Muslim holy fasting month of Ramadan, at the start of the Iranian workweek, following stilted negotiations and warnings from Trump about the threat Iran’s nuclear capabilities posed.

About 12 hours after the attacks began, the U.S. military reported no U.S. casualties and minimal damage at U.S. bases despite “hundreds of Iranian missile and drone attacks.” It said the targets included Revolutionary Guard command facilities, air-defense systems, missile and drone launch sites, and military airfields, while Israel said it killed Iran’s Revolutionary Guard commander and Iran’s defense minister as well as the secretary of the Iranian Security Council.

Iran responded by firing missiles and drones toward Israel and toward U.S. military bases in the region, and exchanges continued into the night, according to AP. An Iranian diplomat told the United Nations Security Council that hundreds of civilians were killed and wounded in the strikes, while Israeli officials and Trump separately described the operation as necessary to disable Iran’s nuclear capabilities.

At the neighborhood level in Tehran, AP reported that some residents expressed celebration as news of Khamenei’s death spread, including people cheering from rooftops, blowing whistles and letting out ululations, while mourners in Iran’s holy city of Mashhad raised a black mourning flag over the Imam Reza shrine and the government declared 40 days of public mourning and a seven-day nationwide holiday.

Beyond Iran and Israel, the escalation raised concerns for the region and for shipping and energy markets, AP reported. With a large share of the world’s oil exports passing through the Strait of Hormuz by sea, officials in Saudi Arabia, Bahrain, Kuwait, Qatar and Jordan said they faced attacks or disruptions, while a civil aviation authority in Kuwait said a drone targeted the main international airport and injured employees.

In the United States, Democrats criticized Trump for acting without congressional authorization, and a spokesman for the White House, Karoline Leavitt, said the administration had briefed several Republican and Democratic leaders in Congress in advance.