US officials say they are not aware of any details of the attack that Russia claims targeted President Vladimir Putin.

White House National Security spokesman John Kirby denied on Thursday any US involvement in the attack on Wednesday, which Moscow said targeted President Vladimir Putin. Kirby stressed that Washington is not even aware of the details of what happened.

“Obviously it’s a ludicrous claim. The United States had nothing to do with this,” Kirby told CNN. “We don’t even know exactly what happened here, but I can assure you the United States had no role in it whatsoever.”

Earlier on Thursday, Kremlin spokesperson Dmitry Peskov said the US, a key ally of Ukraine, was “undoubtedly” behind the attack.

“We know very well that decisions about such actions, about such terrorist attacks, are made not in Kyiv but in Washington,” Peskov said.

In a separate interview with MSNBC on Thursday, Kirby said Peskov was lying, “pure and simple”.

Russia had said on Wednesday that it shot down two drones aimed at the Kremlin before they reached Putin’s official residence.

Ukrainian President Volodymyr Zelenskyy has denied his country’s involvement in the attack, saying that Ukrainians are fighting Russian troops on Ukrainian territory and would leave Putin’s fate to a war crimes tribunal.

US and Ukrainian officials have voiced scepticism about the attack, with Zelenskyy saying that Putin is looking for ways to motivate Russians to continue to fight in Ukraine.

“I would take anything out of the Kremlin with a very large shaker of salt,” US Secretary of State Antony Blinken said on Wednesday after reports of the attack.

Asked whether the US, the top source of military assistance to Ukraine, would back Ukrainian attacks inside Russia, Blinken stressed that Washington does not dictate to Kyiv how to conduct its war efforts.

“We leave it to Ukraine to decide how it’s going to defend itself, and how it’s going to try to get back the territory that’s been seized from it,” he said.

But Kirby suggested on Thursday that the US wants the fighting confined to the battlefield in Ukraine.

“We’ve been clear with them publicly, we’ve been clear privately, that we do not encourage nor do we enable them to strike outside Ukraine,” he said.

Moscow’s war effort in Ukraine has been mired by military setbacks, as Western powers stepped up financial and military support to Kyiv.

On Thursday, Kirby said the US is “committed” to continuing its assistance to Ukraine, citing President Joe Biden as saying that Washington’s support will go on “as long as it takes”.