Russia fired scores of missiles and drones at targets across Ukraine on Sunday, crashing into energy and rail infrastructure and residential buildings, just two days before the fourth anniversary of Moscow's all-out invasion.

The capital Kyiv, regularly targeted by Russian missile and drone attacks since the start of the full-scale invasion, has faced waves of overnight strikes in recent weeks as Moscow has intensified assaults amid freezing winter temperatures.

"Moscow continues to invest in strikes more than in diplomacy," Ukrainian President Volodymyr Zelensky said of the attack on social media, adding that Russia launched about 50 missiles and 300 drones overnight.

"The main target of the attack was the energy sector. Ordinary residential buildings were also damaged, and there is damage to the railway."

The intense barrage came the same day Hungary said it would block the EU's latest package of sanctions against Russia, unless Ukraine re-opens a key oil pipeline that supplies the country.

Ukraine says the Druzhba pipeline that crosses its territory to deliver Russian oil to Slovakia and Hungary was damaged late January by Russian strikes.

In Kyiv and its region, the Sunday overnight strikes killed one man and wounded a dozen more, among them four children, Ukraine's national police said.

AFP saw rescuers sifting through debris of a largely destroyed two-storey house in Kyiv's suburb of Sofiivska Borshchagivka.

"I felt the building shaking. It was clearly a hit, and the force (of the explosion) was strong. I jumped up because my dog got scared too," Olga, a 48-year-old woman who lives in the settlement, told AFP.

Anton, also from the area, said there were no military installations in Sofiivska Borschagivka. "Only people live here -- schools, kindergartens, private houses — so it's definitely not connected to any military facilities or any kind of industry," he said.

- 'Act of terrorism' -

The Russian army said it had carried out a mass strike targeting facilities used by Ukraine's military, saying all targets were hit, in a standard comment for such attacks.

The Russian bombardment on Ukraine, which included ballistic and cruise missiles, prompted heightened vigilance across the country, all the way to the western border.

Ukraine's energy ministry said consumers in six eastern and southeastern region were without power after the strikes.

Authorities in Russia's western Belgorod region, meanwhile, said two man died after a Ukrainian drone strike.

Poland's Operational Command said early Sunday it scrambled jets after detecting "long‑range aviation of the Russian Federation conducting strikes on the territory of Ukraine".

In one attack, an explosion rocked a store in central Lviv, a western Ukrainian city near the Polish border far from the front line that has been largely spared the worst of the conflict.

Explosions ripped through a central shopping street at around midnight, killing a policewoman and wounding 25 people after officers responded to a reported break‑in.

Hours later, law enforcement said it had detained a Ukrainian woman suspected of carrying out the bomb attack, adding that an investigation was ongoing.

"This is clearly an act of terrorism," mayor Andriy Sadovyi said.

Ukraine's interior ministry later said "there is every reason to believe that the crime was committed on the orders of Russia".

- Ukraine 'not losing' -

Ukraine will on Tuesday mark four years since the start of Russia's assault on February 24, 2022. The war that has shattered towns, uprooted millions and killed large numbers on both sides.

Moscow occupies close to a fifth of Ukrainian territory and continues to grind forward, especially in the eastern Donbas region, despite heavy losses and repeated Ukrainian strikes on logistics.

Zelensky told AFP on Friday that Ukraine was "definitely not losing" the war and that victory remained the goal.

He said Ukrainian forces had clawed back about 300 square kilometres (116 square miles) of territory in recent counter‑attacks, gains AFP could not immediately verify.

The United States is pushing both sides to end fighting, brokering several rounds of talks in recent weeks without a clear breakthrough.