With future military aid looking uncertain, uncomfortable questions are being asked as to what "victory" Ukraine could realistically achieve against Russia.
The sidelining of the Abrams reflects evolving battlefield tactics where drone use has made it virtually impossible for them to maneuver without detection.
After Congress approved a long-delayed $61bn in US military aid to Ukraine this week, Russia gloated that advanced western weapons would not turn the tide on the battlefield. More
Two people were wounded after Russia launched a "massive attack" on energy infrastructure in Ukraine overnight from Friday to Saturday, Kyiv's armed forces and local authorities said.
The Associated Press has learned that the Ukrainian Defence Forces have withdrawn US-supplied Abrams tanks from the front line because of the threat of attacks by Russian drones, while the Americans complain that the Ukrainians are not using the equipment more effectively.
According to senior U.S. military officials, Russian surveillance drones and hunter-killer drones have changed the situation on the ground substantially, increasing the vehicles' risk of detection.
Russia has ceased its use of Shahed kamikaze drones against Ukraine for several days, suggesting potential preparation for a large-scale attack, Ukrainian Air Force spokesman Illya Yevlash said on national television on April 26.