The Pentagon has considerably lowered its estimate of the worth of weapons it has despatched to Ukraine, liberating up at the least $3 billion to maintain Ukrainian troops equipped of their struggle in opposition to Russia over the following a number of months.

The Biden administration has confronted intensifying strain to elucidate the way it supposed to proceed supporting Ukraine with out asking Congress to replenish its price range. On Thursday, Pentagon and State Division officers informed congressional workers members that they’d found an accounting subject that might make extra sources out there earlier than Ukraine’s deliberate counteroffensive this summer time.

Pentagon officers realized their mistake virtually two months in the past, in line with a senior White Home official, who spoke on the situation of anonymity to debate accounting processes.

However as an alternative of placating Congress’s issues, the revelation was met with frustration and anger, as some lawmakers criticized the Biden administration for what they stated was an especially troublesome error.

“These funds might have been used for additional provides and weapons for the upcoming counteroffensive, as an alternative of rationing funds to final for the rest of the fiscal yr,” Representatives Michael McCaul of Texas, the chairman of the Home Overseas Relations Committee, and Mike D. Rogers of Alabama, the chairman of the Home Armed Companies Committee, stated in a joint assertion.

They referred to as on the administration to “make up for this valuable misplaced time” by sending long-range missile and cluster munitions to Ukraine, which it has resisted doing.

Administration officers stated their mistake was one in every of improper valuation, explaining that they’d been calculating the worth of every merchandise based mostly on how a lot it could value to switch it with new tools, as an alternative of its sale worth, which is decrease. They plan to make the identical change in an evaluation of their remaining authority to ship Taiwan weapons from current Pentagon shares, in line with administration and congressional officers.

“This overvaluation has not constrained our assist to Ukraine nor impacted our skill to circulate capabilities to the battlefield,” Sabrina Singh, a Pentagon spokeswoman, stated in a press release.

Congressional workers members expressed incredulity that it had taken the administration 15 months of struggle to determine such a primary and but pivotal accounting mistake. Some stated they thought that the revision is likely to be a approach for officers to take care of provides at a time when out there funds for Ukraine have been in peril of operating out.

However they added that they’d not but decided whether or not the adjustment would end in a windfall of extra weaponry for Ukraine.

Lawmakers from each events have repeatedly requested the administration the way it supposed to stretch its dwindling price range authority to provide Ukraine with weapons shortly — referred to as presidential drawdown authority — with out handicapping Kyiv’s efforts to mount a decisive counteroffensive in opposition to Russia this summer time.

“I’m frightened that it’s going to go away a spot,” Senator Susan Collins of Maine, the highest Republican on the Senate Appropriations Committee, stated in an interview Wednesday, earlier than workers members have been informed about accounting revision. “I’m involved that the administration has not been forthcoming on how rather more cash they want, and at what interval will the funds that we’ve appropriated run out.”

“They should have the munitions they want and the capabilities that they want, and I feel we’d like this massive push this summer time, to punch Putin within the mouth a couple of extra occasions,” stated Consultant Elissa Slotkin, a Democrat from Michigan and a former C.I.A., State Division and Pentagon official who’s on the Home’s Armed Companies Committee.

Presidential drawdown authority permits the administration to tug from current weapons shares, as an alternative of ready the a number of months or years it could actually take for protection contractors to fabricate weapons beneath new contracts. The Biden administration has highlighted this system as one in every of its signature achievements in serving to Ukraine battle Russian forces.

Beneath drawdown authority, the administration decides which weapons to ship out from current shares and the right way to decide their worth. For the reason that begin of the battle, the Pentagon has introduced a brand new drawdown package deal about each two weeks, with every valued within the lots of of hundreds of thousands of {dollars}.

However in line with the administration’s personal calculations, its coffers had been operating low. Congress accredited $14.5 billion in drawdown authority to final via the fiscal yr, which ends on September 30. As of Wednesday, in line with congressional aides, solely $2.7 billion of that was left. That’s not sufficient, they stated, to maintain the present tempo and dimension of navy help packages with out operating out of funds by July or August.

A number of Democratic and Republican workers members stated that State Division and Pentagon officers had sympathized with their issues in personal briefings, together with throughout one final week.

The White Home, the workers members added, had staunchly resisted the thought of approaching Congress to enhance these authorities earlier than the top of the fiscal yr. In accordance with some congressional aides, White Home officers stated Ukraine had stockpiled sufficient tools from earlier navy help packages to mount a long-awaited counteroffensive in opposition to Russian positions. Some lawmakers stated in interviews that they have been informed by administration officers that if Ukraine skilled a shortfall nonetheless, European suppliers like Germany would be capable to bridge it with additional navy donations.

However many senior congressional aides accountable for overseeing the Ukraine navy help applications, in each events, remained unconvinced by these arguments. A number of of them speculated this week that the Biden administration was resisting making an enchantment for extra funds and drawdown authority due to issues that it could be awkward to method Congress whereas negotiating a deal on the debt ceiling, during which Democrats try to protect nondefense discretionary spending that Republicans are threatening to chop.

The senior White Home official stated colleagues wished to see how Ukraine’s counteroffensive progressed earlier than figuring out what different weapons it wanted and the right way to request congressional permission for help to assist that.

Mr. Biden and his high aides have stated they’d assist Ukraine till it received the struggle. However the administration has not but requested new drawdown authority or extra funds for Ukraine to be included within the price range for subsequent fiscal yr, which begins on October 1. Congressional aides fear that the delayed begin to that dialogue might complicate lawmakers’ skill to cross laws authorizing new safety help — and, by extension, that might jeopardize Ukraine’s skill to prevail.

John Ismay contributed reporting.