Kyiv has denied any involvement and accused Russia of readying itself for a major offensive in Ukraine.

Here’s what we know so far about Wednesday’s alleged attack:

Russia’s claim

Moscow said two drones had been used in the alleged attack on Putin’s residence in the Kremlin citadel, but had been disabled by electronic defences.

“We regard these actions as a planned terrorist act and an attempt on the president’s life, carried out on the eve of Victory Day, the May 9 Parade, at which the presence of foreign guests is also planned,” the Kremlin said in a statement.

“The Russian side reserves the right to take retaliatory measures where and when it sees fit.”

The powerful speaker of the lower house of Russia’s parliament, Vyacheslav Volodin, issued a statement demanding the use of “weapons capable of stopping and destroying the Kyiv terrorist regime”.

Ukraine’s denial

Ukrainian President Volodymyr Zelenskyy denied that his country had attacked the Russian capital or its president.

“We don’t attack Putin, or Moscow, we fight on our territory,” Zelenskyy told a news conference in Helsinki, Finland, which he was visiting.

Mykhailo Podolyak, a senior aide to Zelenskyy, called Russia’s drone-attack claim a sign that the Kremlin was planning a major new attack on Ukraine.

He also denied the accusation – the most serious levelled by Moscow at Kyiv in more than 14 months of war – and said it indicated Moscow was preparing a major “terrorist provocation”.

“Ukraine has nothing to do with drone attacks on the Kremlin. We do not attack the Kremlin because, first of all, it does not resolve any military tasks,” he said.

As for the drones over the Kremlin. It’s all predictable… Russia is clearly preparing a large-scale terrorist attack. That’s why it first detains a large allegedly subversive group in Crimea. And then it demonstrates “drones over the Kremlin”. First of all, Ukraine wages an…

— Михайло Подоляк (@Podolyak_M) May 3, 2023

Shortly after the Kremlin’s attack claim, Ukraine reported alerts for air strikes over its capital Kyiv and other cities.

“It wouldn’t be the first time that we’ve seen something like that. At the beginning of the war, there were false flags used by pro-Russian separatists in Russian-controlled territories and that was seen by many as a precursor for a full-scale invasion,” said Al Jazeera’s Charles Stratford.

“But the alleged attack comes at a very critical time when the Ukrainians have been preparing for months for some sort of counteroffensive. Interestingly, over the last couple of minutes or so, we have heard air sirens over Kyiv during the day. We haven’t heard that for some time. So you can imagine the city is tense.”

Where was Putin when this alleged attack took place?

No one was reportedly injured in the attack and Kremlin spokesman Dmitry Peskov said Putin was working at his residence near Moscow on Wednesday.

The previous evening he was officially in St Petersburg, where he met with the director of the Mariinsky opera and ballet theatre, Peskov said.

What’s the context?

Russia announced the alleged attack on the heels of a series of incidents – including train derailments – ahead of the popular World War II victory celebrations.

The May 9 event is when Russia marks the Soviet victory over the Nazis with a huge military parade in what has become a central event for Putin’s rule.

Peskov said the parade in Moscow was going ahead as expected with “no changes to the plans” and that Putin would be taking part as scheduled.

Ahead of the celebrations, Moscow’s mayor announced a ban on unauthorised drone flights over the Russian capital.

Has Russia offered proof of this alleged attack?

There was no independent verification of the reported attack on the Kremlin, which Russian authorities said occurred overnight but presented no evidence to support.

Questions also arose as to why it took the Kremlin hours to report the incident and why videos of it also surfaced that late in the day.

A video posted overnight on a local Moscow news Telegram channel, shot from across the river from the Kremlin, appeared to show smoke rising over the buildings.

According to text accompanying the footage, residents of a nearby apartment building reported hearing bangs and seeing smoke at approximately 2:30am local time (23:30 GMT).

“It is hard to say which kind of drones were used, but apparently we can see footage of something exploding over the Kremlin, across the Red Square,” said Pavel Felgenhauer, a Russian defence analyst who served as a senior research officer in the Soviet Academy of Sciences. “So something was in the air, and it was taken down by the Russian forces.”