President Vladimir Putin said on Tuesday that Ukraine's biggest ever drone strike on Moscow was an attempt to scare and provoke Russia, and air defenses around the capital would be strengthened.
Russia said eight drones targeted civilian areas of Moscow and the Moscow region - with a population of over 21 million - in the early hours of Tuesday but were either shot down or diverted with special electronic jammers.
Putin cast the assault, which brought the 15-month war in Ukraine to the heart of Russia, as a terrorist response that came after Russia struck at Ukraine's military intelligence headquarters several days ago.
Ukraine, Putin said, had chosen the path of attempting "to intimidate Russia, Russian citizens and attacks on residential buildings".
"This is clearly a sign of terrorist activity," he said.
Air defenses around Moscow - which as the capital of the world's biggest nuclear power is already protected by an extensive early warning system - would be strengthened, he said.
A Ukrainian presidential aide denied Kyiv was directly involved in the Moscow attack, but said Ukraine was enjoying watching events and forecast more to come.
"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 said.
There is little sign of peace in one of the deadliest wars in Europe since World War Two, and Moscow has repeatedly warned that the West is escalating the war by supplying Kyiv with so much weaponry.
Moscow under attack
Drone attacks deep inside Russia have intensified in recent weeks with strikes on oil pipelines and even the Kremlin earlier this month. Ukraine denied the Kremlin attack, but The New York Times reported that US intelligence believes Kyiv was responsible.
Drone debris hit some of Moscow's most prestigious areas including Leninsky Prospekt, a grand avenue crafted under Josef Stalin, and the area of western Moscow where the Russian elite - including Putin - have their residences.
Residents in south-western Moscow said they heard loud bangs at around 0200 to 0300 GMT, followed by the smell of petrol. Some filmed a drone being shot down and a plume of smoke rising over the Moscow skyline.
Moscow Mayor Sergei Sobyanin said two people were injured, one of whom was hospitalized, in the early morning attack. Moscow's airports remained open. No deaths were reported.
Russia at war
So far Putin has kept the war in Ukraine far from Moscow, where life has continued relatively normally despite the biggest rupture in Russia's ties with the West since the 1962 Cuban Missile Crisis.
Russia began attacking the Ukrainian capital with swarms of cheaply produced loitering munitions often known as “kamikaze drones” last October and uses them extensively during its regular air strikes across Ukraine.
Prosecutors said incidents occurred in the Odintsovsky District of western Moscow region - where Putin has his Novo-Ogaryovo state residence. The area, the most expensive in Russia, is the home to the country's elite.
Russian state television gave the attacks calm coverage. Many Muscovites carried on with their lives with the fatalism for which they are famous.
On a warm spring day in the city center, residents could be seen taking selfies in front of the Bolshoi Theater while others relaxed in cafes and shopped in the well-stocked luxury stores of Moscow.
Putin has repeatedly cast the conflict in Ukraine as a struggle with what he says is an arrogant and aggressive West which is risking a global war by supporting Ukraine.
Thus far, the war has been described by the Kremlin as a "special military operation". The United States has repeatedly said it does not want a war with Russia and has said Ukraine should not use Western weapons to attack inside Russia.
Russian lawmakers cautioned that there were likely to be more attacks on Moscow, which many said would make it necessary to give the military and security agencies even greater powers.
"The sabotage and terrorist attacks of Ukraine will only increase," said Alexander Khinshtein, from the ruling United Russia bloc.
"It is necessary to radically strengthen defense and security measures, especially in terms of countering drones. This includes finally passing the necessary laws."