The original plan was to send Ukraine 31 of the newer M1A2 Abrams, which could have taken a year or two to build and ship. But officials said the decision was made to send the older M1A1 version, which can be taken from Army stocks and will be easier for Ukrainian forces to learn to use and maintain.

The officials spoke on Tuesday on the condition of anonymity because the plan has not yet been publicly announced. Pentagon officials are expected to make the announcement soon.

The Biden administration announced in January that it would send the tanks to Ukraine — after insisting for months that they were too complicated and too hard to maintain and repair. The decision was part of a broader political maneuver that opened the door for Germany to announce it would send its Leopard 2 tanks to Ukraine and allow Poland and other allies to do the same.

It’s unclear how soon the US would begin training Ukrainian forces on how to use, maintain and repair the tanks. That training pipeline could affect the amount of time it takes for the tanks to be used in battle. The Pentagon will also have to ensure that Ukrainian forces have an adequate supply chain for all the parts needed to keep the tanks running.