Ukrainian rocket strikes have destroyed more than 30 Russian military logistics centres in recent weeks and significantly reduced Russia’s attacking potential, Ukraine’s defence ministry spokesperson said.

The official, Oleksandr Motuzianyk, singled out the role played by U.S.-produced HIMARS rocket systems, one of several types of long-range weapon supplied by the West to help Ukraine fight back against Russia.

“In the last weeks, over 30 of the enemy’s military logistical facilities have been destroyed, as a result of which the attacking potential of Russian forces has been significantly reduced,” Motuzianyk said on national television.

Motuzianyk told Reuters in separate comments that the 30 targets were destroyed by multiple launch rocket systems, including HIMARS.

If confirmed, the comments would suggest that Western weapons are having an impact on the battlefield and could indicate a shift in the war’s dynamic after nearly five months.

Russia, which invaded Ukraine on Feb. 24, has captured a chunk of territory in southern Ukraine and used its artillery supremacy in the east to make gradual territorial gains, eventually capturing Luhansk region.

A top Ukrainian general said on Thursday that Russia had not taken a “single metre” of land in the last week and that Ukrainian strikes were disrupting Russian supply lines, forcing Moscow to keep its ammunition further back from the front line. Reuters was not able to immediately confirm battlefield reports.

HIMARS have a longer range and are more precise than Ukraine’s Soviet-era artillery, allowing Ukrainian forces to hit Russian targets that were previously unreachable.

On Friday, Ukraine’s defence minister said Kyiv had taken receipt of a first consignment of M270 multiple rocket launch systems, without specifying which country provided them.

Russia on Thursday criticised the United States and Britain for helping train Ukraine’s armed forces, calling it part of NATO’s “hybrid warfare” against Moscow. It said Washington was providing Ukraine with instructors to help use HIMARS.

Kyiv said this week that its forces carried out strikes on Russian military infrastructure in a city that lies deep in Russian-occupied territory in southern Ukraine.

Motuzianyk also said that only 30% of Russian strikes were hitting military targets, with the rest landing on civilian sites. That assertion could not be verified by Reuters. Russia denies deliberately targeting civilians in what it calls a “special military operation” in Ukraine.