WASHINGTON — The Biden administration has decided to provide cluster munitions to Ukraine and is expected to announce on Friday that the Pentagon will send thousands as part of a new military aid package worth up to $800 million for the war effort against Russia, according to people familiar with the decision.

The decision comes despite widespread concerns that the controversial bombs can cause civilian casualties. The Pentagon will provide munitions that have a reduced “dud rate,” meaning there will be far fewer unexploded rounds that can result in unintended civilian deaths.

U.S. officials said Thursday they expect the military aid to Ukraine will be announced on Friday. The weapons will come from Pentagon stocks and will also include Bradley and Stryker armored vehicles and an array of ammunition, such as rounds for howitzers and the High Mobility Artillery Rocket System, known as HIMARS, officials said.

Long sought by Ukraine, cluster bombs are weapons that open in the air, releasing submunitions, or “bomblets,” that are dispersed over a large area and are intended to wreak destruction on multiple targets at once.

The officials and others familiar with the decision were not authorized to publicly discuss the move before the official announcement and spoke on condition of anonymity.

Ukraine’s Request for Cluster Munitions

Ukrainian officials have asked for the weapons to aid their campaign to push through lines of Russian troops and make gains in the ongoing counteroffensive. Russian forces are already using cluster munitions on the battlefield and in populated civilian areas, U.S. officials have said.

According to the International Committee of the Red Cross, some cluster munitions leave behind “bomblets’’ that have a high rate of failure to explode — up to 40% in some cases. U.S. officials said Thursday that the rate of unexploded ordnance for the munitions that will be going to Ukraine is less than 3% and therefore will mean fewer threats left behind to civilians.

At Pentagon briefing Thursday, Brig. Gen. Pat Ryder said he had no announcement to make about cluster munitions. He said the Defense Department has “multiple variants” of the munitions and “the ones that we are considering providing would not include older variants with (unexploding) rates that are higher than 2.35%.”

Ryder would not say whether Defense Secretary Lloyd Austin has reached out to NATO counterparts to address some of their concerns on the use of cluster munitions. Ryder said the U.S. is aware of reports that indicate some munitions have higher unexploding rates.

If the decision was made to provide the munitions to Ukraine, he said the U.S. “would be carefully selecting rounds with lower dud rates, for which we have recent testing data.”

Asked how the cluster munitions, if approved, would help Ukraine, Ryder said they can be loaded with charges that can penetrate armor and fragment so they can hit multiple personnel — “a capability that would be useful in any type of offensive operations.“ Ryder said the Russians have been using cluster munitions that have a very high dud rate.

Oleksandra Ustinova, a member of Ukraine’s parliament who has been advocating that Washington send more weapons, noted that Ukrainian forces have had to disable mines from much of the territory they are winning back from Russia. As part of that process, Ukrainians will also be able to catch any unexploded ordnance from cluster munitions.

“We will have to de-mine anyway, but it’s better to have this capability,” Ustinova said.

She credited Congress for pushing the administration over several months to change its position on the munitions.

Rep. Michael McCaul, chairman of the House Foreign Affairs Committee, said the move was long overdue.

Congressional Support for Providing Cluster Munitions

“Now is the time for the U.S. and its allies to provide Ukraine with the systems it needs from cluster munitions to F-16s to ATACMS in order to aid their critical counteroffensive. Any further delay will cost the lives of countless Ukrainians and prolong this brutal war,” said McCaul, R-Texas.

The Army Tactical Missile System, known as ATACMS, would give Ukraine the ability to strike Russian targets from as far as about 180 miles (300 kilometers).

Army Gen. Mark Milley, chairman of the Joint Chiefs of Staff, said last week that the U.S. has been thinking about providing the cluster munitions “for a long time.”

“The Ukrainians have asked for it, other European countries have provided some of that, the Russians are using it,” Milley said during a speech at the National Press Club.

Cluster bombs can be fired by artillery that the U.S. has provided to Ukraine, and the Pentagon has a large stockpile of them.

America’s Previous Use of, and Controversy Around Cluster Munitions

The last large-scale American use of cluster bombs was during the 2003 invasion of Iraq, according to the Pentagon. But U.S. forces considered them a key weapon during the invasion of Afghanistan in 2001, according to Human Rights Watch. In the first three years of that conflict, it is estimated the U.S.-led coalition dropped more than 1,500 cluster bombs in Afghanistan.

Proponents of banning cluster bombs say they kill indiscriminately and endanger civilians long after their use. Groups have raised alarms about Russia’s use of the munitions in Ukraine.

A convention banning the use of cluster bombs has been joined by more than 120 countries who agreed not to use, produce, transfer or stockpile the weapons and to clear them after they’ve been used.

The United States, Russia and Ukraine are among the countries that have not signed on.

It is not clear how America’s NATO allies would view the U.S. providing cluster bombs to Ukraine and whether the issue might prove divisive for their largely united support of Kyiv. More than two-thirds of the 30 countries in the alliance are signatories of the 2010 convention on cluster munitions.

Laura Cooper, a deputy assistant secretary of defense focusing on Russia and Ukraine, recently testified to Congress that the Pentagon has assessed that such munitions would help Kyiv press through Russia’s dug-in positions.