So-called "Ghost" drones that are part of a new $800 million U.S. arms package for Ukraine were rapidly developed by the U.S. Air Force for Kyiv and have similar capabilities as armed "Switchblade" drones, the Pentagon said on Thursday.

"This was rapidly developed by the Air Force in response specifically to Ukrainian requirements," Pentagon spokesman John Kirby said.

The White House said earlier on Thursday that over 121 Phoenix Ghost Tactical Unmanned Aerial Systems would be provided to Ukraine as part of the new arms package.