More women and children have been reported killed in Gaza in less than two months than the roughly 7,700 civilians documented as killed by U.S. forces and their international allies in the entire first year of the invasion of Iraq in 2003, according to estimates from Iraq Body Count, an independent British research group.

And the number of women and children reported killed in Gaza since the Israeli campaign began last month has already started to approach the roughly 12,400 civilians documented to have been killed by the United States and its allies in Afghanistan during nearly 20 years of war, according to Neta C. Crawford, co-director of Brown University’s Costs of War Project.

These comparisons are based on the thousands of deaths directly attributed to U.S. coalition forces over decades in Iraq, Syria and Afghanistan. Far more people — hundreds of thousands in total — are estimated to have been killed in these conflicts by other groups, including the Syrian government and its allies, local militias, the Islamic State and the Iraqi security forces.

But while the overall death tolls in those wars were larger, the number of people killed in Gaza “in a very short period of time is higher than in other conflicts,” said Professor Crawford, who has extensively researched modern wars.

In the nine-month battle of Mosul, which Israeli officials have cited as a comparison, an estimated total of 9,000 to 11,000 civilians were killed by all sides in the conflict, including many thousands killed by the Islamic State, The Associated Press found.

A similar number of women and children have already been reported killed in Gaza in less than two months.

The bombs being used in Gaza are larger than what the United States used when it was fighting ISIS in cities like Mosul and Raqqa, and are more consistent with targeting underground infrastructure like tunnels, said Brian Castner, a weapons investigator for Amnesty International and a former explosive ordnance disposal officer in the U.S. Air Force.

Not only is Gaza tiny when compared with conflict zones like Iraq, Afghanistan or Ukraine, but the territory’s borders have also been closed by Israel and Egypt, giving civilians few, if any, safe places to flee.

More than 60,000 buildings have been damaged or destroyed in the Gaza Strip, satellite analysis indicates, including about half of the buildings in northern Gaza.

“They are using extremely large weapons in extremely densely populated areas,” Mr. Castner said of Israeli forces. “It is the worst possible combination of factors.”

Israeli officials say their campaign is focused on degrading Gazan military infrastructure that is often built near homes and civilian institutions — or buried underneath them.

“To get to that target,” Lieutenant Colonel Conricus said, the military has to use “larger bombs with a higher yield.”

When an Israeli government spokesman, Mark Regev, was asked in an Oct. 24 interview with PBS about the pace of the strikes, he said Israel was aiming for a shorter campaign than the United States waged in Iraq and Syria.

“Hopefully, we get it done quicker,” Mr. Regev said. “That’s one of our goals. But it could take longer than many Israelis would hope, because Hamas has been in power for 16 years.”

Israel has directed Gaza residents to evacuate areas where the bombing campaign is especially concentrated, but it has continued to strike other areas as well.

More broadly, Israeli officials say this is a campaign on its own borders to wipe out Hamas, a group dedicated to Israel’s destruction. “The war here is for our existence,” one Israeli war cabinet minister, Benny Gantz, told reporters on Nov. 8.

The brutality of the Hamas attack on Oct. 7 traumatized Israelis, and some prominent members of the Israeli government have made clear that they are waging a ferocious campaign.

“Gaza won’t return to what it was before. Hamas will no longer exist. We will eliminate everything,” Yoav Gallant, Israel’s defense minister, said in the days after the Hamas raids.

After initially questioning the death toll in Gaza, the Biden administration now concedes that the true figures for civilian casualties may be even worse.

Barbara Leaf, the assistant secretary of state for Near Eastern affairs, told a House committee this month that American officials thought the civilian casualties were “very high, frankly, and it could be that they’re even higher than are being cited.”

International experts who have worked with the Gaza Health Ministry during this and other wars say that it gathers death figures from hospitals and morgues across the enclave, which tally the dead and report the names, ID numbers and other details of people killed.

While the experts urged caution around public statements about the specific number of people killed in a particular strike — especially in the immediate aftermath of a blast — they said the aggregate death tolls reported by the Gaza Health Ministry have typically proved to be accurate.

In the last few weeks, recording the dead in Gaza has become increasingly difficult in the chaos of the fighting, as hospitals come under direct fire, much of the health system ceases to function and other government officials have begun updating the number of killed instead of the ministry. But even before those changes, the number of women and children reported dead already outpaced other conflicts.

Women and children account for nearly 70 percent of all deaths reported in Gaza even though most combatants are men — an “extraordinary statistic,” Rick Brennan, the regional emergency director for the World Health Organization’s Eastern Mediterranean office, said at an event this month.

Normally, one would expect the opposite, Mr. Brennan said. In past clashes between Israel and Hamas, for example, about 60 percent of the reported deaths in Gaza were men.