The US Pentagon overcharged by about $3 billion for US equipment sent to Ukraine, a senatorial aide and a defense official told Reuters today, an accounting error that creates the possibility of sending more weapons to Kiev in its war against Russian forces.

The accounting error was the result of assigning a higher-than-guaranteed value to weapons taken from US stockpiles and then sent to Ukraine, two senior defense officials said today.

“We discovered inconsistencies in the way we value the equipment we gave” to Ukraine, one of the senior defense officials told Reuters. The officials and the senator’s aide spoke on condition of anonymity. Congress will be briefed on the accounting adjustment later today, the sources said.

The official said the amount of overpriced weapons is likely to be higher as the Pentagon examines the situation more thoroughly.

As of August 2021, the US has shipped approximately $21.1 billion worth of weapons to Ukraine from its stockpile.

It is uncertain how Congress will react to this finding of the accounting error, and the change in the valuation of the equipment could delay President Joe Biden’s administration from asking Congress to approve more funds for Ukraine amid the U.S. debt crisis .