An ambulance and firefighting vehicles are parked outside a multi-storey apartment block following a reported drone attack in Moscow, Russia, May 30, 2023. (REUTERS/Maxim Shemetov)

Drone attacks deep inside Russia have intensified in recent weeks ahead of an expected Ukrainian counter-offensive, with strikes on oil pipelines.

Drone debris hit some of Moscow most prestigious areas including the area of western Moscow where the Russian elite - including President Vladimir Putin - have their residences.

Putin was briefed early in the morning on the drone attacks, the Kremlin said, adding that Russia's air defenses and military had worked well so there was no threat to the Moscow residents.

Moscow Mayor Sergei Sobyanin said two people were injured, one of whom was hospitalized, in the early morning attack. Moscow's airports remained open.