MOSCOW / ST PETERSBURG / RIGA - Russian forces struck Ukrainian military infrastructure and repelled counterattacks in Ukraine over the past day, the Russian Defense Ministry said Wednesday.

Russian forces hit Ukrainian energy and transport facilities, a drone assembly plant, ammunition depots, and troop concentrations in 142 locations during the day, the ministry said in a statement.

"Air defense forces also shot down one guided aerial bomb, four rockets launched by the US-made HIMARS weapon system, and 123 fixed-wing drones," the ministry said.

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In the Donetsk region, 12 Ukrainian counterattacks have been repelled, preventing Ukrainian attempts to break out of encirclement, the ministry said, adding that Russian forces have expanded their control zone and improved their frontline positions.

"Ukrainian forces in this region are suffering heavy losses amid Russian strikes and advances, leaving no options but voluntary surrender," the ministry said.

NATO exercises

NATO forces are practicing a scenario involving the blockade of Russia's Kaliningrad region during their ongoing military exercises, Russian Deputy Foreign Minister Alexander Grushko said in an interview published by the Russian newspaper Izvestia on Wednesday.

"During NATO exercises, scenarios such as the blockade of the Kaliningrad region are being rehearsed. The region of the Baltic Sea is undergoing active militarization, with coalition forces and assets being built up," Grushko said.

READ MORE: Russian intelligence chief accuses NATO of preparing war with Russia

Kaliningrad is a Russian exclave on the Baltic Sea, bordered by Lithuania and Poland, both members of NATO. It hosts the headquarters of Russia's Baltic Fleet.

The NATO Multinational Brigade in Latvia is undergoing the active phase of its Resolute Warrior military exercises.

Grushko noted that the Baltic region had long been a region of collaboration, where local issues were resolved peacefully. "Now ... this part of Europe has been turned into a zone of confrontation," Grushko said.

READ MORE: Europe steps up sanctions on Russia, provides more support for Ukraine

Latvia, Ukraine to strengthen ties

The defense ministers of Latvia and Ukraine on Wednesday signed a memorandum of understanding to strengthen bilateral cooperation in the defense industry, the Latvian Defense Ministry said.

The memorandum reaffirms both countries' commitment to deepening collaboration in defense production, including soldier training, research and development, and the transfer of military technology and expertise.

It also encourages the establishment of joint defense industry enterprises to enhance industrial capacity and innovation.

According to the ministry, Latvia's military assistance to Ukraine this year is expected to amount to 0.3 percent of its gross domestic product.