Russian officials said Wednesday that Ukraine using American weapons to make strikes deep into Russian territory would implicate Ukraine’s Western allies and demand escalation.

The Kremlin spokesman Dimitri Peskov told reporters that Russia would respond if the U.S. allows Ukraine to strike Russian core territory using the long-range ATACMS missile system. “The involvement of the United States of America and European countries in the conflict over Ukraine is direct, and each new step increases the degree of this involvement,” he said.

Peskov’s comments were prompted by Ukrainian officials pressing U.S. Secretary of State Anthony Blinken to allow such strikes.

Vyacheslav Volodin, the chairman of the State Duma, likewise stated that Russia would have to use “more powerful and destructive weapons” if Ukraine began using long-range Western missiles against the Russian interior. 

“Washington and other European states are becoming parties to the war in Ukraine,” Volodin commented in a Telegram post. 

The warnings came a day after Ukraine launched a drone attack on several towns in the Moscow region, killing a 46-year-old woman and hospitalizing three others in a strike on the suburb of Ramenskoye. 

The Russian Foreign Ministry’s spokeswoman, Maria Zakharova, blamed the Ramenskoye attack on the United States and Britain: “No one today has any doubt that the United States, Britain and all this NATO community stand behind all the terrorist attacks that have been carried out on the territory of our country.”