The US says additional military aid to Ukraine worth $2.2bn (£1.83bn) will include long-range missiles capable of doubling its attack range.
It brings the total amount of military aid given to Ukraine to more than $29.3bn (£24.31bn) since February 2022.
The package includes ground-launched small-diameter bombs (GLSDB) which can hit targets 150km (93 miles) away.
But officials refused to be drawn on speculation that the munitions could be used to attack parts of annexed Crimea.
"When it comes to Ukrainian plans on operations, clearly that is their decision," Pentagon spokesperson Brig Gen Pat Ryder told reporters.
"This gives them a longer-range capability, long-range fires capability, that will enable them, again, to conduct operations in defence of their country and take back their sovereign territory, Russian-occupied areas."
Russia illegally annexed the Crimean Peninsula in 2014 and considers it part of its territory. But it has come under sporadic fire from Ukrainian forces in recent months.
Western nations have repeatedly ruled out providing Ukraine with offensive weapons - such as fighter jets - which it could use to strike against Russia itself.