The United States, Britain and France have rejected as “transparently false” Russian claims that Ukraine is preparing to use a “dirty bomb” on its own territory, with Western help, characterizing the claims as an attempt by Moscow to create a pretext for escalating the conflict. Monday marks eight months since Russia invaded Ukraine on Feb. 24.

“The world would see through any attempt to use this allegation as a pretext for escalation. We further reject any pretext for escalation by Russia,” the foreign ministers of the three nations said in a joint statement. They vowed to continue supporting Ukraine in the face of Russia’s “brutal war of aggression.” 

Russian Defense Minister Sergei Shoigu made the claims during a flurry of talks with top defense officials on Sunday, offering no evidence to back up his assertions on so-called dirty bombs — explosive weapons designed to widely disperse radioactive material. Ukraine gave up its nuclear weapons in 1994 in return for a guarantee from Russia that it would not attack Ukraine.

House Speaker Nancy Pelosi (D-Calif.) confirmed Sunday evening that she will represent the United States this week at a Crimea Platform summit, a forum hosted by Ukraine and focused on the peninsula that Russia illegally annexed in 2014. She said she and other leaders will “deliver an unmistakable statement of our solidarity with Ukraine in its fight for freedom.”

Here’s the latest on the war and its ripple effects across the globe.