Investigators examine a damaged building after a reported drone attack in Moscow, Russia, Monday, July 24, 2023. AP
Russia said it had neutralised two Ukrainian drones over Moscow during the night with no casualties reported.
One of the drones crashed close to the defence ministry in the centre of the Russian capital, while the other hit an office building in southern Moscow.
The attacks came a day after Kyiv vowed to "retaliate" for a Russian missile attack on the Black Sea port of Odesa.
AFP reporters at the scene of the strike near the ministry on Komsomolsky Prospekt saw a two-storey building with a damaged roof behind a police cordon.
"I wasn't asleep. It was 3:39am. The house really shook," Vladimir, a 70-year-old local resident, told AFP about the moment of impact.
"It is scandalous that a Ukrainian drone almost flew into the defence ministry," said Vladimir, who declined to give his last name, as he took pictures at the scene.
Polina, a 35-year-old manager out walking her dog, said her husband and child were woken by "a very loud noise right next to our house".
In Crimea, Moscow-installed governor Sergei Aksyonov said Russian forces shot down 11 Ukrainian drones.
He said an ammunition depot was "hit" and a private house "damaged", without providing further details.
Aksyonov said villages near the depot were being evacuated.
Crimea, annexed by Russia in 2014, has been targeted by Kyiv throughout Moscow's Ukraine offensive but has come under more intense, increased attacks in recent weeks.
Kyiv has repeatedly said it plans to take back Crimea.
Meanwhile in southern Ukraine's Odesa region, officials reported a four-hour Russian drone attack on port infrastructure on the Danube River.
"As a result of the strikes, a grain hangar was destroyed, tanks for storing other types of cargo were damaged," Ukraine's southern military command said on Telegram.
The Danube delta region, which spans across Romania and Ukraine, is being used as an export route for Ukrainian grain.
Russia last week pulled out of a key deal which had allowed the safe export of Ukrainian grain through the Black Sea.
Since then Kyiv has accused Russia of targeting grain supplies and infrastructure vital to grain exports.
Ukraine's military said it shot down three of the drones used in Monday's attack.
"According to initial reports, about four workers of the port were injured, but the information is still being clarified," it said.
'Suppressed and crashed'
Russia's defence ministry branded the Moscow drone attack a "terrorist act".
"Two Ukrainian drones were suppressed and crashed. There are no casualties," it said.
Moscow Mayor Sergei Sobyanin said the drone strikes occurred at around 4:00 am local time (0100 GMT).
"There was no serious damage," he said.
The RIA Novosti news agency posted a video of the business centre, with some damage visible to the top of the tall building.
The road around it was closed.
Moscow and its environs lie around 500 kilometres (310 miles) from the Ukrainian border but have been hit by several drone attacks this year, with one even hitting the Kremlin in May.
Earlier this month, Russia said it had downed five Ukrainian drones that disrupted the functioning of Moscow's Vnukovo international airport.
'Will definitely feel this'
After Russian strikes on Odesa, President Volodymyr Zelensky had vowed retaliation on Sunday.
"They will definitely feel this," he said.
"We cannot allow people around the world to get used to terrorist attacks," Zelensky added.
"The target of all these missiles is not just cities, villages or people. Their target is humanity and the foundations of our entire European culture."
A strike on the city on Sunday killed two people and severely damaged a historic cathedral.
Clergymen rescued icons from rubble inside the badly damaged Transfiguration Cathedral, which was demolished under Stalin in 1936 and rebuilt in the 1990s after the collapse of the Soviet Union.
The Ukrainian government condemned the cathedral strike as a "war crime", saying it had been "destroyed twice: by Stalin and Putin".
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