The heavy bombs that President Biden has held back from sending to Israel have been a major point of controversy in the Gaza war, as a key tool for Israel’s decimation of the territory.
Biden has paused a shipment of some 3,500 bombs, which includes heavy 2,000-pound versions along with the lighter 500-pound munitions. Both have been used to devastating effect in Gaza, swaths of which have been reduced to rubble.
Israel says the bombs are critical to taking out Hamas targets, but the Biden administration has drawn the line on their use in any large-scale offensive into the densely packed southern Gaza city of Rafah.
Human rights groups have for months said that U.S. bombs in Gaza have inflicted a costly toll on civilians and have pointed to instances of indiscriminate Israeli attacks — and some Democrats are saying Biden should have stopped supplying them sooner.
“For months, I have strongly urged the Biden administration to prioritize Israel’s defensive needs … rather than offensive weapons that could cause enormous suffering in Gaza and further escalate tensions across the region.,” Sen. Tim Kaine (D-Va.) said in a statement last week.
Stephen Miles, president of the progressive advocacy group Win Without War, said 2,000-pound bombs have a “dramatic effect” when dropped in dense areas and by using them, Israel is “knowingly taking action” that leads to “innocent people dying.”
“There’s no way to use these bombs in the Gaza Strip without causing massive harm,” he said. “The munition is designed for maximum depth of destruction. It is not designed to be used in tightly packed communities in dense urban environments.”
Even before the Gaza war, the U.S. was set to deliver about $3 billion a year to Israel through 2028. That’s now set to be far higher after Congress approved billions more last month at Biden’s request to help Israel’s fight to eliminate Palestinian militant group Hamas.
More than 100 U.S. foreign military sales have been approved to Israel since Oct. 7, when Hamas invaded southern Israel, killed some 1,200 people and took another roughly 250 hostages.
That military aid includes artillery shells, air defense munitions and bombs, along with fighter jets and small arms that Israel has used against Hamas and the Hezbollah military and political group in Lebanon, along with other Iranian-backed groups in the Middle East.
The standard conventional U.S. bombs are the Mark 80 series, which range from the Mark 81 weighing at 250 pounds to the Mark 84 at 2,000 pounds. They are dropped from aircraft onto targets.
Israel employs the bombs as part of its strategy to defeat Hamas, which uses tunnels and hidden networks across Gaza to hide forces, weapons and equipment.
Avi Melamed, a former Israeli intelligence official, said Israel has chosen to put troops on the ground in sensitive areas, including hospitals, instead of dropping bombs. But in challenging situations, such as a deep underground site, it is more effective to deploy heavier bombs.
“There are [some] areas where the use of those bombs is more efficient and more justified, at least from a military perspective, in order to neutralize those targets,” he said.
But heavier bombs generally cause more devastation by creating a larger impact once they hit the ground, and their use has helped drive up the human toll in Gaza, where more than 34,000 people have died in the seven-month war.
In a CNN interview earlier this week, Biden said he would not provide offensive weapons to Israel if troops move into Rafah — where more than a million civilians are sheltering from the war, along with Hamas battalions.
“Civilians have been killed in Gaza as a consequence of those bombs and other ways in which they go after population centers,” Biden told CNN earlier this week.
Pentagon press secretary Maj. Gen. Pat Ryder told reporters that the U.S. was reviewing the 2,000-pound bombs in the context of Rafah.
“We’re focused on the end use, especially rather focused on the end use of the 2,000-pound bombs and the impact that they could have in a dense urban setting as we’ve seen in other parts of Gaza,” he said Thursday. “That’s something that we’ll continue to look at.”
The hold on the bombs — and the threat to pause more weapons — has angered Israel, with Israel Prime Minister Benjamin Netanyahu vowing to fight on alone if needed.
Former Israeli Prime Minister Naftali Bennett told CNN this week that the bombs can “sometimes” cause collateral damage but argued that was a fact in all wars, and he accused Hamas of using human shields in Gaza.
“Is Israel using bombs to target civilians? Absolutely not. Never. We never target civilians,” he said. “In fact, we have the lowest ratio of collateral damage in the history of urban warfare. There’s about, let’s call it, 32,000 Palestinians who died. Half of them are terrorists. That’s 1-to-1.”
“In Afghanistan, in Iraq, it was 1-to-9. For every terrorist you killed, there were six, seven, eight, nine civilians,” he added. “We’re bending over backward in order to prevent unnecessary deaths. Otherwise, we’d get this whole thing done within three days if we didn’t care about it.”
The Hamas-run health agency does not differentiate between civilians and militants in its casualty figures, and some monitors have put forward far lower estimates of the proportion of fighters in the overall death toll.
Human rights groups and media reports have pointed to several instances of U.S. bombs being misused in Gaza.
International humanitarian law does not prohibit the use of heavy bombs in warfare, but warring parties must prevent indiscriminate attacks and are obligated to take feasible precautions to prevent the deaths of civilians.
CNN reported in December that hundreds of 2,000-pound bombs were used in the first month of the war, creating around 500 different 40-foot craters in diameter. At least one incident involved a big bomb airstrike in the Jabalia refugee camp in late October, which killed more than 100 people.
And The New York Times reported also in December that 2,000-pound bombs were dropped in areas of southern Gaza where civilians had been told to move toward for safety.
Amnesty International identified several strikes that it alleged were unlawful and involved U.S. bombs.
Amanda Klasing, national director for government relations with Amnesty International USA, said some of the 2,000-pound bombs have been “wiping out whole families,” and because the bombs are “so large,” it’s difficult to minimize collateral damage.
“There isn’t any clear indication that there’s a desire to actually apply international law to the usage of these weapons,” she said of the Israeli military. “The risk is still high to the transfer of these arms to the government of Israel.”
Amnesty has also raised concerns about Israel issuing 24-hour mass evacuation notices and limited advance notice before airstrikes.
To reduce casualties, a 2,000-pound or 500-pound “dumb” bomb can also be fitted with Joint Direct Attack Munition (JDAM) kits, which convert the unguided munition into a “smart,” precision-guided bomb.
Klasing said JDAMs and smaller bombs still carry a high risk if not used properly.
“The ability to have more precision has to be paired with intentionality to follow international humanitarian law,” she said. Similarly, “if you don’t change the pattern of how these weapons are deployed and you just change the size of the weapon, that’s not really bringing yourself inline with international humanitarian law.”
A State Department review released Friday found it was “reasonable to assess” that Israel has violated international humanitarian law in Gaza but stopped short of a determinative finding of wrongdoing, because the review did not find specific instances of violations.
Israel and its allies often respond to criticism of the Gaza death toll by pointing to Hamas’s tactics of operating out of areas with dense civilian populations.
Melamed, the former Israeli intelligence official, said Hamas is often operating in “open areas deliberately” because fighters know “that in such a way collateral damage is inevitable.”
“Israel is defending itself, and it’s basically operating to remove the threat in a very challenging environment,“ he said, “which is a massively urban environment where your enemy is using its own brothers and sisters — literally, its own brother and sisters — as a human shield.”
The debate comes ahead of a potential invasion of Rafah, where Israeli troops have already entered for limited operations and taken control of a key border crossing with Egypt.
Gaza is a densely packed area, but about 1.3 million Palestinians are crammed into Rafah, and the city could face unprecedented destruction in the event of a massive Israeli operation, said Miles from Win Without War.
“The reason you see the concerns about Rafah is because as horrific as what we’ve seen already, the scale [of potential large fighting] there is almost unimaginably worse,” he said.
“That’s why it was heartening to see the president finally take some action. But I think we’re a long way from the end.”