The Ukrainian military has targeted missile launch sites in Russia, which has helped to ease the pressure on the besieged city of Kharkiv, its mayor told Reuters on Tuesday.

His remarks came after U.S. President Joe Biden late last month authorized the use of American weapons to strike targets inside Russia that were being used to attack Kharkiv, Ukraine’s second-largest city located near the Russian border.

While missile and drone attacks continue, Ihor Terekhov said the change has contributed to a relative “calm.”

“This has helped,” Terekhov said in an interview in Berlin, when asked whether the ability to strike inside Russia had eased the situation following weeks of heavy bombardment.

“That is why maybe Kharkiv has … this period of … calm the last couple of weeks … that there were no great strikes as it was, for example, in May.” He was speaking through a translator.

Terekhov is visiting Germany, which aims to encourage European support and investment in Ukraine.

The mayor said that about 11,500 people had arrived in Kharkiv city from regions that were being actively bombarded.

Terekhov also highlighted the need for Western air defenses to help protect his city.

Ukraine has struggled to intercept incoming Russian drones and missiles due to the lack of systems to shoot them down. Kyiv’s allies are scrambling to find more, but deliveries have been hampered by bureaucratic delays and the lack of availability of suitable weapons.

“It is very important to have the weapons on time. It is very important to have these weapons, especially the multi-defense air system.”

Russia launched three guided bombs at Kharkiv on Monday, damaging at least two houses, according to local officials, emphasizing the continuing threat.

The city and surrounding region have long been targeted by Russian attacks but the strikes had become more intense in recent months, hitting civilian and energy infrastructure.

In recent months, Moscow’s forces have made slow but steady gains along several parts of the sprawling eastern front and are attempting to push deeper into the northeastern Kharkiv region.

The regional capital has been repeatedly hit by Russian bombs and missiles, including an attack on a printing works that killed seven people and another on a DIY hardware store in late May that killed at least 14.