More than 1,000 civilians have died in the first five days of of Iran, including 181 children under 10, according to the U.S.-based .

The rights group stated it had compiled reports of 1,097 civilian fatalities and over 5,000 injuries so far in the war, which began in the early hours of Saturday with a massive wave of airstrikes across the country that killed Iran’s and other Iranian military and political leaders.

It noted an additional 880 reported deaths are currently under review for verification and classification.

TIME cannot independently confirm the casualty figures, and the number of children reported killed in the school strike has ranged from 108 to 181.

This news comes as Secretary of Defense Pete Hegseth announced airstrikes would escalate across Iran, telling reporters on Wednesday that U.S. forces were delivering “death and destruction from the sky all day long.” 

“Our warfighters have maximum authorities granted personally by the president and yours truly,” Hegseth said. “Our rules of engagement are bold, precise, and designed to unleash American power—not shackle it. This was never meant to be a fair fight. And it is not a fair fight. We are punching them while they are down, which is exactly how it should be.”

The Israel Defense Forces, meanwhile, said in a Wednesday morning statement it had launched “broad scale strikes targeting Iranian terror regime targets in Tehran.”

Videos from Tehran showed large explosions across the capital on Wednesday. Iran’s state television reported a mourning ceremony for Khamenei had been postponed due to intensive airstrikes in the city.

HRANA said “a range of sites and infrastructure, including several military bases, two medical centers, and one residential area,” were hit by airstrikes between March 2 and 3—including reported damage to Shohada Hospital in Sarpol-e Zahab and a field hospital in Salas-e Babajani.

The rights group added the strikes could violate humanitarian law but emphasized these are “preliminary findings and remains subject to verification.”

When asked to comment on the civilian death toll claims, U.S. Central Command (CENTCOM) directed TIME to Tuesday’s remarks by Admiral Brad Cooper, CENTCOM’s commander. 

“We’ve just begun,” Cooper said in the video . He also noted the U.S. has struck nearly 2,000 targets in the first 100 hours of the operation.

In Lebanon, the health ministry said Israeli strikes have killed 72 people and displaced more than 83,000.

Iran’s retaliatory strikes have hit U.S. bases and across the Middle East since Saturday, as well as civilian areas in Gulf countries and Israel. Those attacks have killed at least 11 people in Israel and three in the United Arab Emirates. Six U.S. service members have also died in the fighting so far.  

A school tragedy 

The worst civilian casualty of the war to date occurred in the opening wave of Saturday strikes, when a girls’ elementary school in southern Iran was bombed while children were in class.  

The strike hit Shajareh Tayyebeh School in Minab—a city in Iran’s southern Hormozgan province—on Saturday morning, the start of the school week in . 

Shiva Amelirad, a Canada-based representative of the Coordinating Council of Iranian Teachers’ Trade Associations (a network of Iranian teachers’ unions), that at least 108 children died in the attack, based on information from sources in Minab.

Thousands gathered in Minab on Tuesday for a mass funeral for the children killed in the strike. Iran’s state television showed parents holding photographs of the children they lost and coffins draped in the Islamic Republic’s flag being carried through the crowd. 

A U.N. panel of experts said Wednesday it was “deeply disturbed” by the incident—which it said killed more than (citing reports)—and noted most victims appear to be schoolgirls aged 7 to 12. 

“The Committee is alarmed by reports of strikes on civilian infrastructure, including schools and hospitals, which have injured and traumatised children, and claimed many young lives,” the U.N. Committee on the Rights of the Child said in a statement.

UNESCO, the U.N. education agency, it “a grave violation of the protection afforded to schools under international humanitarian law.”

When asked about the school strike Wednesday, Hegseth said: “We’re investigating that. We, of course, never target civilian targets.”

Amnesty International raised concerns for civilians in Iran and across the region on Tuesday. 

“Aerial attacks impacting schools, medical facilities or residential buildings, as well as the firing of ballistic missiles and other explosive weapons with wide area effects into densely populated areas, raise grave concerns of possible violations of international humanitarian law,” said Agnès Callamard, Amnesty International’s Secretary General, . 

“Parties to the conflict must immediately refrain from and cease unlawful attacks—whether direct attacks on civilians, indiscriminate and disproportionate attacks, or the use of explosive weapons with wide area effects in densely populated areas. They must take all feasible precautions to prevent civilian harm,” she added.