The Biden administration announced Friday it would send cluster munitions to Ukraine despite concerns from many Democratic lawmakers about civilian harm.

Ukrainian leaders and Republican lawmakers have spent months urging President Joe Biden to green-light the controversial weapons, which are explosives that release smaller submunitions over a certain area. Their use is banned by an international treaty with more than 100 participants, although the United States and Ukraine are not among them.

The dual-purpose improved conventional munitions, or DPICMs, were unveiled as part of a broader $300 million security assistance package that also includes Patriot air defense system munitions, AIM-7 missiles for air defense and HIMARS artillery ammunition.

Jake Sullivan, Biden’s national security adviser, defended the decision to provide the cluster munitions at a White House briefing Friday, noting Russia’s extensive use of them on the battlefield. He also said the “dud rate” of the U.S. weapons — the failure rate, which would signify ongoing risk to civilians — was significantly lower than that of their Russian counterparts.

“We recognize the cluster munitions create a risk of civilian harm from unexploded ordnance. This is why we deferred the decision for as long as we could,” Sullivan said. “But there is also a massive risk of civilian harm if Russian troops and tanks roll over Ukrainian positions, and take more Ukrainian territory, and subjugate more Ukrainian civilians because Ukraine does not have enough artillery.”

Several Democratic lawmakers spoke out against the decision. Rep. Betty McCollum, D-Minn., ranking member of the House Appropriations Defense Subcommittee, called the move “unnecessary and a terrible mistake.”

“Allowing legacy U.S. cluster munitions onto the battlefield in Ukraine undermines our moral authority and places the U.S. in a position that directly contradicts 23 of our NATO allies who have joined the Convention on Cluster Munitions,” she said in a statement. “The legacy of cluster bombs is misery, death, and expensive cleanup generations after their use.”

Rep. Sara Jacobs, D-Calif., a member of the House Armed Services Committee who opposes cluster munitions, has introduced a floor amendment to the fiscal 2024 defense authorization bill that would prohibit their transfer, though it’s unclear if Republican leaders will make it in order when the House considers NDAA next week.

Some Democrats, however, offered their support to Biden. Sens. Mark Kelly of Arizona, Tammy Duckworth of Illinois and Joe Manchin III of West Virginia, all members of the Senate Armed Services Committee, released statements backing the move Friday.

Congress has prohibited the transfer of cluster munitions with dud rates higher than 1 percent. Biden waived that requirement to approve cluster munitions with a dud rate of below 2.5 percent, Defense Undersecretary for Policy Colin Kahl told reporters Friday.

‘It’s their citizens’

Sullivan downplayed the risk of the U.S. cluster munitions to Ukrainian civilians and said officials in Kyiv had provided “assurances” that the weapons would be used responsibly.

Ukraine “has every incentive to minimize risk to civilians because it’s their citizens,” he said. “It’s Ukrainians who they are trying to protect and defend. This is not Ukraine taking these and going and using them in the Middle East or in Southeast Asia, or in some faraway land.”

Meanwhile, the news won praise from Republican defense hawks who had pressed the Biden administration to make cluster munitions available. GOP lawmakers have long faulted Biden for delays in approving various weapon systems that could provide crucial capabilities for Kyiv.

“While no weapons system is a proverbial golden bullet, DPICMs will help fill a key gap for Ukraine’s military and will allow the Ukrainian Armed Forces to target and eliminate Russian forces more efficiently, including in fortified positions on the battlefield,” House Foreign Affairs Chairman Michael McCaul, Senate Foreign Affairs Committee ranking member Jim Risch and Senate Armed Services Committee ranking member Roger Wicker said in a statement Friday.

Those lawmakers also reiterated pleas for the Biden administration to send Army Tactical Missile System long-range guided missiles to Ukraine and to expedite delivery of F-16 jets.

“This administration’s misguided fear of escalation in providing critical weapon systems — from Stingers to HIMARS to Abrams tanks and now to DPICMs — has only served to prolong the war, embolden Vladimir Putin, cost Ukrainian lives, and, indeed, put the entire Ukrainian counteroffensive at risk of failure,” they said.