President Joe Biden has authorized the provision of antipersonnel land mines to Ukraine, two U.S. officials said, a step that will bolster Kyiv’s defenses against advancing Russian troops but has drawn criticism from arms control groups.

The move comes in the wake of the White House’s recent authorization allowing Ukraine to use a powerful long-range missile system to strike inside Russia - part of a sweep of urgent actions the lame-duck Biden administration is taking to help Kyiv’s faltering war effort.

Russian President Vladimir Putin has warned that Moscow will retaliate for the latest missile strikes from the Army Tactical Missile System, or ATACMS. Shipping antipersonnel land mines to Ukraine is also potentially controversial, though among a different group: More than 160 countries have signed an international treaty banning their use, noting that the indiscriminate weapons can cause enduring harm to civilians. But Kyiv has sought them since Russia invaded nearly three years ago, and the Kremlin’s forces have deployed antipersonnel land mines liberally on the front lines, impeding Ukraine’s progress as it seeks to reclaim its own territory.

The Biden administration is deeply concerned about Russia’s assaults against Ukraine’s front lines in recent weeks and sees a pressing need to blunt the advance, officials said. The Pentagon believes that the provision of the mines is among the most helpful steps the Biden administration can do to help slow Russia’s attack, officials said.

One official said the type of antipersonnel land mine is “nonpersistent,” meaning that the mines self-destruct or lose battery charge to render them inactive, reducing the danger to civilians. The official said that Ukrainian policymakers had committed to not deploying the mines in densely populated areas. Arms control experts said that even nonpersistent mines pose a safety hazard.

The official and three others spoke about the decision on the condition of anonymity to candidly discuss sensitive internal White House deliberations.

“Russia is attacking Ukrainian lines in the east with waves of troops, regardless of the casualties that they’re suffering,” one of the officials said. “So the Ukrainians are obviously taking losses, and more towns and cities are at risk of falling. These mines were made specifically to combat exactly this.”

“When they’re used in concert with the other munitions that we already are providing Ukraine, the intent is that they will contribute to a more effective defense,” the official said.

Biden had been reluctant to supply Ukraine with the mines in the face of concerns within his own administration and from a wide range of anti-mine advocates who say the risk to civilians is unacceptably high. But Russia’s battlefield progress in recent months has forced the White House to find fresh ways to help Kyiv, especially following the victory of President-elect Donald Trump, who has vowed to steer the conflict toward a swift conclusion.

Use of the mines would be limited to Ukrainian territory, with an expected focus on eastern Ukraine, one of the officials said. Russian forces have made significant advances in the Donetsk region and in recent months have gained territory at the fastest rate since 2022. Ukrainian troops have struggled to build strong defensive lines in the face of relentless drone sorties and small assault teams. Land mines could help them shore up their defenses by slowing enemy troops and channeling them to areas where they can be targeted with artillery and rockets.

Neither Russia nor the United States is one of the 164 parties to the Ottawa Convention, also known as the Mine Ban Treaty, that prohibits the deployment and transfer of antipersonnel land mines. Biden in 2022 revived an Obama-era policy that banned the transfer and use of U.S. antipersonnel land mines outside the Korean Peninsula.

One Ukrainian official welcomed any policy change despite the potential risks that would come with widespread deployment of the weapons.

“Russia uses them anyway,” the official said, speaking on the condition of anonymity because of the subject’s sensitivity.

But some human rights campaigners said that the U.S. decision to provide antipersonnel land mines to Ukraine - a signatory to the Mine Ban Treaty - is a black mark against Washington.

“It’s a shocking and devastating development,” said Mary Wareham, deputy director of the crisis, conflict and arms division at Human Rights Watch, the advocacy group, who said that even nonpersistent mines hold risks for civilians, require complicated cleanup efforts and are not always reliably deactivated.

The Trump administration in 2020 had reversed the Obama-era policy, pointing to the need for strategic use of mines to counter adversaries like Russia and China, and drawing strong condemnation from arms control advocates.

“It will put more civilians at risk of being injured by unexploded mines, and is unnecessary from a military perspective,” Biden, as a presidential candidate, said in response to Trump’s decision, calling it “reckless.”

The United States had a stockpile of about 3 million antipersonnel land mines as of 2022. The mines had not been used since 1991, during the first Gulf War, apart from a single 2002 incident in Afghanistan involving a lone munition, the State Department said in 2022.

The Biden administration has already committed to supporting mine-clearance efforts in Ukraine after the end of the conflict. One of the U.S. officials said that the administration will extend that commitment to helping clean up the U.S.-supplied mines.

The Ukraine conflict has spurred other countries to reevaluate their opposition to antipersonnel land mines. The Baltic nations of Lithuania, Latvia and Estonia considered withdrawing from the Ottawa Convention earlier this year in order to bolster their defenses against Russian aggression, although they ultimately decided to reinforce stocks of antitank mines and other tools that are less hazardous to civilians.

Siobhán O’Grady in Kyiv and Ellen Nakashima in Washington contributed to this report.