A swarm of drones hit Moscow on Tuesday in an unprecedented attack, while Russian drones struck Kyiv for a third straight day as Ukraine gears up for a major offensive against Russian forces.
The Russian defence ministry blamed Kyiv for the attacks that saw three drones crash into residential buildings in Moscow.
The Russian defence ministry said that eight drones were used in the attack, adding that five of them were downed and three disabled.
Of the three that hit residential buildings, two crashed into high-rises located in Moscow's affluent southwest, while a third damaged a residential building in a suburb of the capital.
The other drones fell outside Moscow. Some of the debris was found around 15 kilometres from President Vladimir Putin's Novo-Ogaryovo residence.
One video shared on social media showed an explosion followed by a column of smoke rising into the sky.
Two drones were intercepted over the Kremlin earlier this month but Tuesday's attack was the first time that unmanned aerial vehicles hit residential areas of Moscow, hundreds of kilometres from the front lines in Ukraine.
The Kremlin insisted that the was no "threat" to Russians, adding that Putin was being informed of the attacks in "real time".
- 'No fear' -
Moscow also said it believed the attack was a "response" by Kyiv to a recent Russian hit in Ukraine.
"It is completely clear that we are talking about response acts by the Kyiv regime to very effective strikes on a command centre (in Ukraine)," Kremlin spokesman Dmitry Peskov said, without clarifying where the Russian strike took place.
Mykhailo Podolyak, an adviser to Ukrainian President Volodymyr Zelenskiy, said Kyiv had "no direct relation" to the Moscow attacks.
Moscow mayor Sergei Sobyanin said two people had sought medical assistance after the raid but "no-one has suffered serious injuries".
The residents of buildings damaged in the strikes were briefly evacuated.
On Profsoyuznaya Street, a residential building with a blown-out window was cordoned off by police but the atmosphere was calm, with children playing outside and locals walking their dogs, an AFP correspondent saw.
Some of the residents were moved to a nearby school, where they drank tea and watched a Soviet-era movie.
Valentin Yemelyanov, a 50-year-old IT worker, who lives on the same street but closer towards the centre of Moscow, said there was "no fear or panic".
"The damage is minimal," he told AFP. He said he was "not surprised" by the drone attack, given the escalation of the conflict. "It is obvious that things are going this way."
Muscovites told Russian journalists that a drone had also crashed into an apartment on the 14th floor of a high-rise on Leninsky Prospekt but did not explode.
- Explosions -
Andrei Vorobyov, the governor of the Moscow region, said several drones had also been downed near the capital.
"This morning the residents of certain districts in the Moscow region could hear explosions. It was our anti-air missile defence system," he wrote.
"Several drones were shot down while approaching Moscow," he added.
Since the start of Russia's assault on Ukraine, drone attacks have hit targets outside Moscow, including military installations located far from the front.
Yevgeny Prigozhin -- the head of mercenary group Wagner, whose forces are fighting in Ukraine -- accused the defence ministry of inaction, releasing a new statement peppered with swear words.
Also on Tuesday, Ukraine said it had downed 29 out of 31 drones, mainly over Kyiv and the Kyiv region in the latest Russian barrage -- the third on the Ukrainian capital in 24 hours.
On Monday, Russia fired a barrage of missiles at Kyiv, sending panicked residents running for shelter in an unusual daytime attack following overnight strikes.
The latest barrages landed as the Ukrainian capital was still recovering from a drone attack at the weekend, the biggest since Russia began its campaign in Ukraine in February last year.
Kyiv received its first shipments of USn-made Patriot surface-to-air missile system in April and US President Joe Biden on Monday suggested more aid was to come.
Asked about Russia's barrage of attacks on Kyiv, Biden told reporters, "It's not unexpected."
"That's why we've got to continue to give Ukraine all that it needs."
Kyiv has been preparing a counter-offensive, although its timing and focus have been the subject of months of speculation.