Col. Martin O'Donnell, a spokesman for US Army Europe and Africa, told VOA that all of the Ukrainians who trained on the tanks with US forces in Germany have also returned to Ukraine, along with ammunition and spare tank parts.
"We have lived up to our end of the bargain. From this point forward, it is up to them [Ukraine] to determine when and where they will deliver this capability," O'Donnell said.
Military officials say it could take time before the Abrams are sent to the battlefield, as Ukrainian troops make sure they have needed support elements in place and determine when and where to use the tanks for greatest effect against Russian forces.
"I think Ukraine will be deliberate in when and where they use it," O'Donnell said. "The Abrams tank is one hell of an armored vehicle, but it's not a silver bullet. Ultimately, it's Ukraine's determination to break through that matters most."
The first of the 31 American-made Abrams tanks were delivered to Ukraine late last month, according to Ukrainian President Volodymyr Zelenskyy.