Ukraine has the right to self-defense. This right includes the right to destroy legitimate military targets on the territory of Russia. This was stated by NATO Secretary General Jens Stoltenberg during a telethon, according to a correspondent of UNN .
We must not forget that this war was unleashed by Russia as the aggressor. Russia has occupied part of Ukraine. Ukraine has the right to self-defense. This right to self-defense includes the right to destroy legitimate military targets on the territory of the aggressor, Russia. We have provided 99% of the military assistance to Ukraine, although there are certain restrictions on the use of these weapons. However, we will ease these restrictions as Russia has launched a new offensive in the north near Kharkiv
He noted that the occupiers are attacking from Russian territory.
Ukraine has the right to destroy the missile launchers used to fire on Kharkiv. So, the restrictions are gradually being lifted, and this will help Ukrainians defend themselves
Addendum
The White House has clarified its position on allowing Ukraine to strike targets in Russia with American weapons, and did not rule out that this authorization could be extended.