Russia on Saturday blamed the U.S. for an attack on a pro-Kremlin writer that killed his assistant and left him wounded.
The head of the Russian paramilitary group Wagner meanwhile asked Moscow to let Chechen fighters relieve his forces at the flashpoint city of Bakhmut in eastern Ukraine.
Earlier Saturday, investigators said Ukraine was behind the blast that wrecked the car in which Zakhar Prilepin, one of Russia's best-known novelists, was traveling.