Ukraine has broadened a request for controversial cluster bombs from the United States to include a weapon that it wants to cannibalize to drop the anti-armor bomblets it contains on Russian forces from drones, according to two U.S. lawmakers.

Kyiv has urged members of Congress to press the White House to approve sending the weapons but it is by no means certain that the Biden administration will sign off on that. Cluster munitions, banned by more than 120 countries, normally release large numbers of smaller bomblets that can kill indiscriminately over a wide area, threatening civilians.

Ukraine is seeking the MK-20, an air-delivered cluster bomb, to release its individual explosives from drones, said U.S. Representatives Jason Crow and Adam Smith, who both serve on the House of Representatives Armed Services Committee. That is in addition to 155 mm artillery cluster shells that Ukraine already has requested, they said.