Ukrainian drones struck wealthy districts of Moscow on Tuesday, Russia said in what one politician called the most dangerous attack on the capital since World War Two, while Kyiv was also hit from the air for the third time in 24 hours.
Since Russia sent tens of thousands of troops into its neighbour in February 2022, the war has largely been fought inside Ukraine.
Aerial strikes on targets far from the front have intensified amid a ragged stalemate on the ground with Russian forces entrenched along an extended line in Ukraine's east and south.
One of the strategic southern places Russian forces have controlled since nearly the beginning of the invasion is the Zaporizhzhia nuclear power plant, and on Tuesday the United Nations nuclear watchdog chief asked Ukraine and Russia to respect five principles to safeguard the station. Neither Ukraine nor Russia have committed to respect the principles.
International Atomic Energy Agency (IAEA) chief Rafael Grossi has been trying for months to secure an agreement to reduce the risk of a catastrophic nuclear accident from military activity like shelling at Zaporizhzhia, Europe's biggest nuclear power plant.
In a briefing to the U.N. Security Council, Grossi said the principles included that there should be no attack on or from the plant and that it not be used as a base for heavy weapons and military equipment. He called for off-site power to the plant to remain available and secure.
"The nuclear safety and security situation at the Zaporizhzhia nuclear power plant ... continues to be extremely fragile and dangerous," Grossi said. "Military activities continue in the region and may well increase very considerably in the near future."
Russia's U.N. Ambassador Vassily Nebenzia said: "Mr. Grossi's proposals to ensure the security of the Zaporizhzhia nuclear power plant are in line with the measures that we've already been implementing for a long time."
Ukraine's Ambassador to the U.N. Sergiy Kyslytsya said the principles "must be complemented with the demand of full demilitarization and deoccupation of the station."
INJURIES AND EVACUATIONS IN MOSCOW
Commenting on the early Tuesday morning air attacks in Moscow, the defence ministry said eight drones sent by Ukraine and targeting civilians were shot down or diverted with electronic jammers, though Baza, a Telegram channel with links to the security services, said there were more than 25.
Mykhailo Podolyak, a Ukrainian presidential aide, denied Kyiv was directly involved but said "we are pleased to watch events" and forecast more such strikes.
Two people were injured while some apartment blocks were briefly evacuated, according to Moscow's mayor. Residents said they heard loud bangs followed by the smell of petrol. Some filmed a drone being shot down and a plume of smoke.
The drones targeted some of Moscow's most prestigious districts including where Russian President Vladimir Putin and the elite have residences. He was later in the Kremlin and received a briefing on the attack, a spokesman said.
Putin later said Ukraine's biggest drone strike on Moscow was an attempt to frighten and provoke Russia, and that air defences around the capital would be strengthened.
Civilian targets in Kyiv and other Ukrainian cities have since the earliest days of the war been struck repeatedly by Russian drones and missiles.
But Tuesday marked only the second time Moscow had come under direct fire.
In Washington, the White House said it was still gathering information on the reports of drones striking in Moscow.
"We do not support attacks inside of Russia. That's it. Period," White House press secretary Karine Jean-Pierre said at a briefing. Washington is a major supplier of weaponry to Ukraine on the condition it uses it to defend itself and to retake Ukrainian territory occupied by Russian forces.
Russian lawmaker Maxim Ivanov called it the most serious assault on Moscow since Nazi Germany's invasion in World War Two, saying no Russian could now avoid "the new reality".
Russian state television gave the attacks calm coverage, and many Muscovites shrugged them off. Olga, who said she lived near to the site of one of the drone collisions on Profsoyuznaya Street, called the strikes "logical, to be expected ... what else were we waiting for?"
Meanwhile, Russia put Ukraine's top generals on a "wanted list", RIA news agency said.
KYIV CITY HIT 17 TIMES BY AIR STRIKES IN MAY
Ukraine said four people died around the country in Russia's latest attacks, with 34 wounded including two children.
Ukrainian air defence shot down 29 of 31 Iranian-made Shahed drones in Kyiv, the armed forces general staff said.
A 33-year-old woman died on her balcony when debris from a destroyed Russian projectile hit a Kyiv highrise, officials said.
Russia has assaulted Kyiv 17 times in May with drones or missiles, mostly at night.
In a Tuesday evening video address, Ukrainian President Volodymyr Zelenskiy appeared to suggest some authorities were not doing enough to protect citizens during air raids.
"Shelters in cities have to be accessible. People should understand when and how the number and availability of shelters will increase," he said, but did not elaborate.
(Reporting by Guy Faulconbridge, Max Hunder, Olena Harmash, Pavel Polityuk, Valentyn Ogirenko, Gleb Garanich, Lidia Kelly, Trevor Hunnicutt and Steve Holland; Writing by Andrew Cawthorne, Mark Heinrich and Grant McCool; Editing by Michael Perry, Giles Elgood, Alison Williams and Richard Chang)