Moscow said Ukrainian drone attacks on Russian territory would "not be possible" without US and NATO help, escalating its rhetoric after reporting it had downed five drones near the capital on Tuesday.
Ukraine meanwhile accused Russia of planning "dangerous provocations" at the Moscow-controlled Zaporizhzhia nuclear power plant, while Russia in turn claimed Kyiv was planning to attack the facility, Europe's largest.
"These attacks would not be possible without the help provided to the Kyiv regime by the US and its NATO allies," the Russian foreign ministry said, claiming the West was "training drone operators and providing the necessary intelligence to commit such crimes."
It marks the latest in a series of recent drone attacks -- including on the Kremlin and Russian towns near the border with Ukraine -- that Moscow has blamed on Kyiv.
The Russian military said it had downed all five drones and that there was no damage or casualties from the early-morning attacks.
Emergency services cited by the state-run RIA Novosti news agency said one of the drones was "neutralised" at Kubinka, about 40 kilometres (25 miles) from Vnukovo international airport, where air traffic was briefly disrupted.
In early May, two drones were shot down above the Kremlin, and later the same month drones hit Moscow high-rises.
Ukrainian President Volodymyr Zelensky on Tuesday warned his French counterpart Emmanuel Macron that Russia was planning "dangerous provocations" at the Moscow-occupied Zaporizhzhia nuclear power plant.
"We agreed to keep the situation under maximum control together with the IAEA" UN nuclear watchdog, he added after his phone call with the French leader.
The Ukrainian health ministry urged residents to be ready for a "possible evacuation" if there is an explosion at the site.
Russia and Ukraine have regularly accused each other of putting the plant's safety at risk since the start of the conflict.
Kyiv claimed "objects similar to explosive devices were placed on the outer roof of the third and fourth reactors" at the site.
In his evening address, Zelensky said the idea was "perhaps to simulate the hit on the plant."
"Maybe they have some other scenario. But in any case, the world sees it," the Ukrainian leader said.
"Radiation is a threat to everyone in the world."
In Moscow, an advisor to Russia's Rosatom nuclear agency, Renat Karchaa, told state television: "On July 5, literally at night, in the dark, the Ukrainian army will try to attack the Zaporizhzhia nuclear power plant".
He claimed Ukraine planned to use "high-precision, long-range weapons" as well as drones.
- Burning, overturned cars -
Ukraine said 43 people, including 12 children, were injured in a Russian strike on the town of Pervomaisky in the eastern Kharkiv region on Tuesday.
The strike hit a parking lot outside a residential building in the town of around 28,000 people.
The head of Kyiv's presidential office Andriy Yermak distributed images of burned and destroyed cars.
The governor of the Kharkiv region, Oleg Synegubov, posted a video from the scene, showing smoke rising from burnt cars near a Soviet-era housing block.
Authorities also announced that Russian shelling on a residential area in the southern frontline city of Kherson had killed two people.
Early Tuesday Ukraine said Russia had launched 22 Iranian "Shahed" attack drones and three missiles at the Sumy, Donetsk and Zaporizhzhia regions.
Its forces had "destroyed" 16 of the drones, it said.
- Journalist attacked -
In Chechnya, an award-winning Russian investigative journalist was beaten by armed assailants and taken to hospital, her newspaper and a rights group said.
The attack happened early on Tuesday as well-known journalist Elena Milashina and Alexander Nemov, a lawyer, were travelling from the airport.
Her newspaper, Novaya Gazeta, published a video of Milashina in hospital with her head shaven and covered in a green-coloured dye -- used to target Kremlin critics -- and her hands bandaged.
She said the attack, which included having a gun held to her head, was linked to her "professional activity in Chechnya."
Milashina has for years covered rights abuses in the Caucasus republic ruled by former warlord Ramzan Kadyrov.
In Kyiv, around 200 people attended a ceremony on Tuesday in St Michael's cathedral for the Ukrainian writer Victoria Amelina, who died of her wounds in a Russian strike on a restaurant in eastern Ukraine.