During the night leading up to Monday, Ukraine's air force followed how Russian bomber planes moved in Russian airspace and how attack drones were on their way in swarms. The attacks came from all directions and targeted at least 15 of the country's 24 regions.
Explosions thundered in, among other places, Kiev during the morning hours. Four civilian fatalities have been reported, all in different locations. In one of the cases, a man was killed when a multi-family house was damaged in the city of Lutsk in northwestern Ukraine.
Ukraine's President Volodymyr Zelensky describes it as one of the largest Russian attacks so far.
More than a hundred rockets of various kinds and around a hundred "Shahed" (attack drones), he says in a video clip published on social media.
At least a dozen civilians have been injured in the attacks, several of them in southern Ukraine in the area attacked from the direction of the Black Sea.
Kiev's mayor Vitalij Klitjko reported early in the morning about major power outages in the city and some problems with the water supply. Local media reported that many of the capital's residents sought shelter in, among other places, subway stations.
Major power companies in the country have introduced emergency stops in power supply due to the morning's attacks.
Russia's military claims that "all targets were hit", which is difficult to verify since they basically describe all their own efforts as successful.