Ukrainian President Volodymyr Zelenskiy said Kyiv had nothing to do with the incident, purportedly caught on videos published on Russian social media channels.
Analysts told Reuters that if indeed the drones were sent to Moscow by Ukraine, the intent was likely a "messaging" operation meant to show it could penetrate defences in the Russian capital, rather than an attempt on Putin's life.
"So, it could be a symbolic strike into the heart of Moscow to demonstrate that basically no part of European Russia is safe from a Ukrainian attack," said Samuel Bendett, a senior fellow at the Center for a New American Security in Washington, D.C.
The RIA news agency said Putin had not been in the Kremlin at the time and was working on Wednesday at his Novo Ogaryovo residence outside Moscow.
Two of the numerous videos published on Russian social media channels show two objects flying on the same trajectory toward one of the highest points in the Kremlin complex, the dome of the Senate. The first seemed to be destroyed with little more than a puff of smoke, the second appeared to leave blazing wreckage on the dome.
"Ukraine has several types of drones that can fit the profile. For example, its newly developed UJ-22 drone can actually fly the distance," Bendett said. "It's commercial drone that they acquired from China - its Mugin-5 cargo drone, which can be basically purchased online and could be refitted into a military drone - that drone can fly several hundred kilometers and it was used in previous attacks."
Reuters checks on time and location indicated that the videos could be authentic, though some Western analysts said it was possible Russia might have staged the incident to pin the blame on Kyiv and justify some kind of crushing response.
"I think that's a bit far-fetched," said Alexander Vindman, a former National Security Council official in the White House and a senior fellow at Johns Hopkins University's School of Advanced International Studies (SAIS). By staging the attack, Vindman said, Moscow would be "undermining the criticality of demonstrating Russia as a secure, powerful state."
Bendett said it's also possible that neither Kyiv nor the Kremlin is behind the attack.
"It could have been an operation by nonmilitary actors, someone basically anti-Russian, but not necessarily with the blessing of the Ukrainian government,” he said.
Russia says it launched its "special military operation" 14 months ago to counter a threat from Kyiv's relations with the West. Ukraine and its allies call it an unprovoked war of conquest by Moscow, derailed by a failed assault on the capital Kyiv early last year and Ukrainian advances in the second half of 2022.
Over the past five months, Ukrainian ground forces have kept mostly on the defensive, while Russia launched a huge, largely unsuccessful winter assault, capturing little new ground.
Reuters