Russia launched a barrage of missiles and drones at targets across Ukraine Sunday, striking energy and rail infrastructure as well as residential buildings just two days before the fourth anniversary of the invasion.

There were reports of a series of blasts in Kyiv starting at around 4 a.m. (2 a.m. GMT), shortly after an air raid alert was issued, with the air force later widening the alert nationwide, citing the threat of missiles.

"Moscow continues to invest in strikes more than in diplomacy," Ukrainian President Volodymyr Zelenskyy commented on the attack on social media, saying 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."

One man was killed and a dozen more people were wounded, among them four children, in and around Kyiv, Ukraine's national police said.