Russian authorities have shifted the blame in what they say was an attempt to assassinate President Vladimir Putin. They had accused Ukrainian officials, who denied any involvement. On Thursday, they accused US leaders.

The Russians said, on Wednesday, two drones were deployed over the Kremlin in what they called a "terrorist act." They said Putin was not there at the time. They said their electronic defenses disabled the drones.

Putin's spokesperson, Dmitry Peskov, accused US officials of telling the Ukrainians where to strike. "It's very important that those in Washington understand that we know this, and that they understand the dangers of such direct involvement," he said.

US officials are still trying to figure out what happened. But White House National Security Council spokesperson John Kirby said Peskov's claims are "ludicrous."

Analysts with the Institute for the Study of War, which is based in Washington, said the possibility of drones penetrating multiple layers of air defense is "extremely unlikely."

Ukrainian President Volodymyr Zelenskyy went to The Hague to renew his calls that Russian officials be prosecuted for war crimes. Judges with the International Criminal Court issued an arrest warrant for Putin in March.

"The aggressor must feel the full power of justice," Zelenskyy said. "This is our historical responsibility of the modern generation to make the total punishment for aggression inevitable." He called for an independent tribunal, invoking the trials of Nazi leaders in Nuremberg.