This is the moment a drone which Russia claimed was being used by Ukraine to try to assassinate President Vladimir Putin exploded at the Kremlin.
The so-called assault on the Kremlin is said to have left smoke rising above the building, although there were no casualties.
Russia branded the incident a "terrorist act" and said military and security forces "disabled" the drones before they could strike.
A statement said debris from two unmanned aerial vehicles fell on the grounds of the seat of Russia's government, but did not cause any damage.
Ukraine said it had “nothing to do with attacks on the Kremlin” and it is possible it was a “false flag” to justify attacks on Ukraine’s civilians.
President Volodymyr Zelenskyy, on an unannounced visit to Helsinki for talks with the leaders of five Nordic countries, denied any role in the attack.
"We don't attack Putin or Moscow. We fight on our territory. We're defending our villages and cities," he said at a news conference.
It could also be an attempt to justify a future missile attack on Ukraine figures, including President Volodymyr Zelensky's Kyiv residence.
But former Russian president Dmitry Medvedev - now a top Putin security official - demanded the death of Zelensky and the rest of the Ukrainian leadership.
In a chilling statement, he said: “After today’s terrorist attack, there are no options left except for the physical elimination of Zelensky and his cabal.
"It is not even needed to sign an act of unconditional surrender.”
Imagery apparently shot across the river from the Kremlin, showed what looked like smoke rising over the building.
Residents of a nearby apartment building reported hearing bangs and seeing smoke at around 2.30am local time on Wednesday.
The Kremlin preparing to observe its annual Victory Day on Tuesday May 9 and said in a statement: "We consider these actions as a planned terrorist act and an attempt on the life of the president of Russia, carried out on the eve of the Victory Day, the parade on May 9, where foreign dignitaries are expected.”
Kremlin spokesman Dmitry Peskov said President Putin was not in the Kremlin at the time and was working from his Novo-Ogaryovo residence.
Russia added that Putin was safe and his schedule was unchanged despite the fiery incident.
Shortly before the news about the alleged attack broke, Moscow mayor Sergei Sobyanin issued a ban on using drones in the Russian capital.
Overnight on Wednesday huge blasts rocked a secret Russian FSB spy base in Crimea's capital Simferopol as Moscow's security teams hunted down a "sabotage" team.
The FSB claimed it had seized saboteurs with explosives linked to rail blasts earlier this year.
The agency says they have detained a team planning to assassinate local Moscow-appointed officials.
One of the team is apparently a Bulgarian-Ukrainian national.
Ukraine claims more than 500 Russian soldiers killed in the past day, along with the destruction of 16 artillery systems and 28 drones.
More than 40 Ukrainian houses were damaged overnight in shelling overnight from Tuesday to Wednesday, although no casualties reported.
And the Russian death toll, according to Kyiv, is hurtling towards the bloody milestone of 200,000 with as many as 192,000 killed since the beginning of war, 3,701 tanks destroyed and 947 cruise missiles brought down by air defences.
