WASHINGTON — The Biden administration is expected to announce it will send Ukraine cluster munitions for its ongoing counteroffensive against Russia — a brutal weapon that the White House only last year declared could constitute a “war crime” if used.

The US for the first time is mulling sending Ukraine dual-purpose improved conventional munitions, chief Pentagon spokesman Air Force Brig. Gen. Pat Ryder said Thursday, without confirming reports that the decision has already been made.

The powerful artillery shells release dozens of smaller explosive submunitions, increasing lethality as they spread to hit multiple targets, similar to how multiple pellets spread from a single shotgun shell.

The move would reverse prior Biden administration concerns about sending such systems, dubbed “cluster munitions,” over the nearly year-and-a-half-long war.

In February 2022, just days into the bloody invasion, former White House press secretary Jen Psaki said that using the weapons, known to kill and maim civilians, was a potential war crime.

“We have seen the reports. If that were true, it would potentially be a war crime,” Psaki responded to questions about reports that Russia was deploying the munitions in Ukraine.

While using cluster munitions in conflict on enemy fighters is allowed under the laws of war, deploying them on the general population is a war crime.

The munitions’ association with war crimes may have contributed to prior hesitance to ship such systems, as senior defense officials have said some US allies express concern over the weapons ending up in the wrong hands.

“What DPICMs bring to a battlefield is anti-armor and anti-personnel capability,” Ryder said. “So essentially, it can be either loaded with shaped charges which are armor-penetrating, or they can be loaded with fragmentary munitions which are anti-personnel.”

The prospect comes after Laura Cooper, the deputy assistant secretary of defense for Russia, Ukraine and Eurasia, told Congress late last month that the Pentagon had concluded that cluster munitions would be useful in the conflict, “especially against dug-in Russian positions on the battlefield.”

Meanwhile, Moscow has already been using cluster munitions on the battlefield and against civilians in Ukraine — something Ryder was quick to point out while speaking to reporters on Thursday.

“Clearly [it’s] a capability that would be useful in any type of offensive operations,” he said.

When and if the US makes the announcement, it would be one of several recent weapons donation decisions that the Biden administration has reversed this year.

In January, Defense Secretary Lloyd Austin announced the US would send Ukraine 31 M1 Abrams tanks just six days after Pentagon spokesperson Sabrina Singh told reporters “it just doesn’t make sense to provide [M1s] to the Ukrainians at this moment” because they use gas-turbine engines that run on jet fuel.

Similarly, Biden in May approved a plan to train Ukrainian troops on F-16 fighter jets in a significant step toward Kyiv receiving the military aircraft after more than a year of pleading.

While the US has not yet pledged to send Ukraine its own F-16s, the Biden decision came with an understanding that the nation would give allies with American-made jets the green light to do so.