"To that end, we are not encouraging or enabling Ukraine to strike beyond its borders," the official said.
"We do not seek to prolong the war just to inflict pain on Russia.".
As such, a decision was made to not provide a "longer range of munitions" and the administration "communicated that to the Ukrainians," according to the official.
Asked whether Ukrainian officials had offered explicit promises not to launch the new systems toward positions within Russia itself, the senior administration official said they had.
The official also emphasized that it was Russia that first attacked Ukraine.
"I think it's important to point out that it is Russia attacking inside Ukraine, not the other way around," the official said.
The events followed a political uprising in Kyiv that brought to power a government seeking closer ties with the West. »