Among the weapons the U.S. is expected to provide are Multiple Launch Rocket Systems, or MLRS, which are mobile artillery launchers that can fire dozens of miles farther than any current system in Ukraine’s control.

The U.S. is also expected to give to Ukraine High Mobility Artillery Rocket Systems, known as Himars. Those are light multiple rocket launchers with a comparable range to the MLRS. But unlike the MLRS, which moves on tracks, the Himars move on a wheeled chassis.

Both systems would give Ukraine more mobility than M777 howitzers, which the U.S. is still sending to Ukraine. It is unclear how many of the new systems the U.S. would provide, but one official said they could arrive in Ukraine within weeks. The U.S. also has said Ukraine forces would need at least a week of training to use them.