Moscow claimed Tuesday that Ukrainian forces were planning to use Western-supplied missiles to strike targets inside Russia and the annexed peninsula of Crimea, threatening “immediate retaliation.”

“The leadership of Ukraine’s armed forces plans to strike Russian territory, including Crimea, with HIMARS and Storm Shadow missiles,” Defense Minister Sergei Shoigu said during a meeting with military officials.

Shoigu warned of swift retaliation in the event the weapons were used to strike targets inside Russia or on the Black Sea territory that Moscow annexed in 2014.

“The use of these missiles outside the zone of the special military operation will mean the United States and Great Britain’s full involvement in the conflict and will entail immediate strikes on decision-making centers in Ukraine,” Shoigu said.

The United States has spearheaded the push for military support for Ukraine, quickly forging an international coalition to back Kyiv after Russia sent troops to Ukraine in February 2022 and coordinating aid from dozens of countries.

Moscow has accused Western countries of directly waging warfare against Russia by arming Ukraine.

In recent weeks drone attacks have struck cities in Russia and targets in Crimea, but Kyiv has not claimed responsibility for the incidents.