A Ukrainian presidential aide denied Kyiv was directly involved in a drone attack on Moscow on Tuesday, but said Ukraine was enjoying watching the events and predicted an increase in such attacks.
Russia said Ukraine had launched its biggest drone attack on Moscow but that air defences destroyed all eight of the drones.
"Regarding the attacks: of course we are pleased to watch and predict an increase in the number of attacks. But of course we have nothing directly to do with this," Ukrainian presidential adviser Mykhailo Podolyak told the Breakfast Show YouTube channel.
He also joked that perhaps some Russian drones - fired at Ukraine - had decided to "come back".
One Russian politician called the drone attack the worst on the capital since World War II, while Kyiv was hit for the third time in 24 hours.
BBC Russia editor Steve Rosenberg said the windows of his home shook during the explosions.
He said the war in Ukraine has been "happening a long way away" from Moscow and hasn't directly impacted people's lives there.
"You feel as if the hostilities are coming much closer to home now," he said.
Since Russia sent troops into its neighbour in February last year, the war has largely been fought inside Ukraine, though Moscow has reported some attacks on its territory including an alleged assassination attempt against President Vladimir Putin.
Moscow Mayor Sergei Sobyanin said the early morning drone assault had injured two people, while some residents in two lightly damaged apartment blocks were briefly evacuated.
Russia's defence ministry said eight drones were sent by Kyiv and all were shot down, though Baza, a Telegram channel with links to the security services, said more than 25 drones were involved. Video on social media showed one apparently being hit with a plume of smoke rising over the Moscow skyline.
Lawmaker Maxim Ivanov termed it the most serious assault on Moscow since the Nazis in World War II, saying no citizen could now avoid "the new reality".
"You will either defeat the enemy as a single fist with our Motherland, or the indelible shame of cowardice, collaboration and betrayal will engulf your family," he said.
Two weeks ago, two drones exploded over the Kremlin in an attack Russia also blamed on Kyiv and said was aimed at Putin.
At a messy stalemate for most of 2023 with Russian troops occupying some eastern Ukrainian regions, the war has killed tens of thousands, uprooted millions, reduced cities to ruins and caused havoc in the global economy.
In Kyiv, Ukrainian defence forces said they shot down more than 20 Iranian-made Shahed drones on Tuesday.
One person died and four were injured when debris from a destroyed Russian projectile hit a high-rise apartment building sparking a fire, Ukrainian officials said. Two upper floors of the building were destroyed with people possibly still under rubble.
'Several waves'
Photos from Kyiv officials and Reuters reporters showed flames engulfing the top of the building.
"The attack was massive, came from different directions, in several waves," Serhiy Popko, head of Kyiv's military administration, said on Telegram.
Neither side confirmed targeting each other's capitals.
Russia has attacked Kyiv 17 times in May with drones or missiles, mostly at night, in an apparent attempt to undermine Ukrainians' will to fight after more than 15 months of war.
"These missile attacks of a fairly dense frequency are aimed specifically at exhausting both our air defence forces and our physical and moral strength," said Natalya Gumenyuk, a spokesperson for Ukraine's southern military command.
President Volodymyr Zelensky said US-supplied Patriot anti-missile defences were doing their job.
"When Patriots in the hands of Ukrainians ensure a 100 percent interception rate of any Russian missile, terror will be defeated," he said in his nightly video address on Monday.
Ukraine is promising a counter-offensive backed with Western weapons to try to drive Russian occupiers from territory seized since Moscow launched what it calls its "special military operation".
On the eastern frontlines, Russian paratroops and motorised units were replacing Wagner mercenary units in the city of Bakhmut, which has been the main focus of fighting for months, according to a Ukrainian military representative.
Moscow said it invaded Ukraine to "denazify" its neighbour and protect Russian speakers. Western opponents say the invasion is an imperialist land grab.
Moscow says it is open to resuming stalled peace talks with Kyiv and has welcomed mediation efforts from Brazil and China.
But Kyiv insists full withdrawal of Russian troops is the only way to end the war.
-Reuters / BBC