Ukraine attacked Moscow on Wednesday with at least 11 drones that were shot down by air defenses in what Russian officials called one of the biggest drone strikes on the capital since its special military operation in Ukraine began in February 2022.

The conflict, largely a grinding artillery and drone battle across the fields, forests and villages of eastern Ukraine, escalated on August 6 when Ukraine sent thousands of soldiers over the border into Russia's western Kursk region.

For months, Ukraine has also fought an increasingly damaging drone war against the refineries and airfields of Russia, the world's second largest oil exporter, though major drone attacks on the Moscow region - with a population of over 21 million - have been rarer.

Russia's defense ministry said its air defenses destroyed a total of 45 drones over Russian territory, including 11 over the Moscow region, 23 over the border region of Bryansk, six over the Belgorod region, three over the Kaluga region and two over the Kursk region.

Some of the drones were shot down over the city of Podolsk, Moscow Mayor Sergey Sobyanin said. The city, located in the Moscow region, is some 38 km south of the Kremlin.

"This is one of the largest attempts to attack Moscow using drones ever," Sobyanin said on the Telegram messaging app in the early hours of Wednesday. "The layered defense of Moscow that was created made it possible to successfully repel all the attacks from the enemy UAVs."

Along Moscow's boulevards, cafes, restaurants and shops of the capital - which has been carefully insulated from the conflict - were crowded with little signs of concern.

Moscow's airports, Vnukovo, Domodedovo and Zhukovsky, limited flights for four hours but restarted normal operations early in the morning, Russia's aviation watchdog said.

Sobyanin said that according to preliminary information, there were no injuries or damage reported in the aftermath of the attacks. There were also no casualties or damage reported following the attack on Bryansk in Russia's southwest, the governor of the region, Alexander Bogomaz, wrote on Telegram.

Ukrainian military's General Staff said in a statement that it struck an S-300 anti-aircraft missile system based in Russia's southern Rostov region overnight.

Rostov governor Vasily Golubev said air defense forces had destroyed a Ukraine-launched missile over his region, but Russia's defense ministry made no mention of the incident in its daily statement on destroyed air weapons.

In Russia's north Murmansk region, local authorities issued a drone attack warning on Wednesday, as local airports imposed flight restrictions following unverified reports of an unmanned aircraft being shot down.

Shortly before the announcement, civil aviation authorities introduced flight restrictions at airports in the regional capital, Murmansk, and the town of Apatity.

No drone attacks have previously been reported in the Murmansk region before. If confirmed, Wednesday's reported drone downing would mark the furthest a Ukrainian drone has flown into Russian territory.

Russia meanwhile is advancing in eastern Ukraine, where it controls about 18 percent of the territory, and battling to repel Ukraine's incursion into the Kursk region, the biggest foreign attack on Russian territory since World War II.

German Chancellor Olaf Scholz said on Wednesday Ukraine had not consulted Berlin about its August 6 shock incursion into Russia and that he expected that military operation to be limited in time and territory.

"Ukraine has prepared its military operation in the Kursk region very secretly and without feedback, which is certainly due to the situation," Scholz said. "This is a very limited operation in terms of space and probably also in terms of time."

Separately, Scholz said Germany would continue to be what he said was Ukraine's biggest supporter in Europe after controversy in recent days over what some have called wavering German support for Kyiv over domestic politicking.