Ukrainian President Volodymyr Zelenskyy said on Friday that Ukraine using any Western weapon to strike Russian territory is "a question of time".

Outgunned and outmanned on the battlefield, Kyiv has been increasing pressure on its Western allies to be able to launch offensive strikes at military targets inside Russia to better repel Russian advances.

"I think that using any weapon, Western kind of weapon, on the territory of Russia is a question of time. Otherwise, it is not about just peace," Zelenskyy told reporters on a visit to Stockholm.

KYIV'S FORCES ARE UP AGAINST A CONCERTED RUSSIAN PUSH IN EASTERN UKRAINE, A MILITARY OFFICIAL SAYS

Ukraine has stressed the urgency for the use of Western-supplied arms to conduct strikes inside Russia as it defends against Russian advances in the northeastern Kharkiv region.

This spring, Ukraine has found itself on the back foot in the 27-month-old full-scale invasion as it faces delays in military aid from the U.S., increased attacks on its energy infrastructure and Russia's push to expand the frontline.

U.S. President Joe Biden has quietly authorized Kyiv to strike military targets inside Russia which support the offensive in the Kharkiv region.

Zelenskyy said Ukraine "got message from the American side early in the morning" on Friday which signified a "step forward" in defending people in villages near the border with Russia. He did not disclose additional details on the communication with the U.S.

Zelenskyy said he did not yet know the possible restrictions related to the use of long-awaited F-16 fighter jets but appealed to the question of fairness in deliberations, saying Ukraine should be able to retaliate against Russian strikes.

Germany, another major ally, signaled its openness to Ukraine's use of its weapons to strike military sites fueling attacks on Kharkiv region.

France has taken a similar stance, saying Ukraine should be allowed to strike military sites Russia is using to attack its territory.