Ukrainian President Volodymyr Zelensky warned on Sunday that "war" was coming to Russia after three Ukrainian drones were downed over Moscow.
"Gradually, the war is returning to the territory of Russia -- to its symbolic centres and military bases, and this is an inevitable, natural and absolutely fair process," Zelensky said on a visit to the western city of Ivano-Frankivsk.
"Ukraine is getting stronger," he added, warning however that the country should prepare for new attack on energy infrastructure in winter.
"But we must be aware that, just as last year, Russian terrorists can still attack our energy sector and critical facilities this winter," Zelensky said, adding that preparations for "all possible scenarios" were discussed in Ivano-Frankivsk.
Zelensky spoke after three Ukrainian drones were downed over Moscow early on Sunday, the Russian defence ministry said. The attack damaged two office towers and briefly shut an international airport.
Separately, Moscow said on Sunday its forces had thwarted a Ukrainian attempt to attack Russia-annexed Crimea with 25 drones overnight.
The attacks reported Sunday were the latest in a series of recent drone assaults -- including on the Kremlin and Russian towns near the border with Ukraine -- that Moscow has blamed on Kyiv.