President Joe Biden has given permission to Ukraine to strike inside Russian territory with American munitions.
However, the head of the White House has limited their use so that Kiev can hit targets over the border near Kharkiv after Russia made significant advances around the city in the northeastern part of the country.
"The president recently directed his team to ensure that Ukraine will be able to use US-supplied weapons for firefighting purposes in Kharkiv so that Ukraine can respond to Russian forces that hit them or prepare to hit them," one of the officials told CNN.
The decision represents a reversal of President Joe Biden's stance, who until now had steadfastly rejected Ukraine's use of American weaponry to carry out attacks inside Russia.
The decision comes amid growing international pressure from close US allies.
But the decision is limited to the area around Kharkiv, and Ukraine has not sought permission beyond that, the official said, adding that they do not foresee the US expanding the permitted area.
Kiev requested that Washington change its policy only in recent weeks as Russian forces have made progress, the official said.
Russian forces, ammunition depots and logistics centers can now be targeted with US-supplied artillery and missiles across the border from Kharkiv in western Russia.