The United Nations says more than 7,000 civilians are confirmed to have been killed in Ukraine since the Russian invasion began last February. But the UN suspects the actual number may be far larger.

The Office of the UN High Commissioner for Human Rights reported on Monday that at least 7,031 civilians were killed in Ukraine from February 24 last year, when the invasion began, through Sunday. It said 433 of the victims were children.

But the office suspects the actual death toll may be far higher due to delays in confirming information from battle zones and areas controlled by Russia.

On Saturday, a missile struck a nine-story apartment building in the eastern city of Dnipro.

Ukraine's emergency authorities say at least 44 people, including four children, were killed, and 79 injured. They say 20 people are still unaccounted for.

Russia's presidential office insists that Ukraine may have misfired the missile, but the British defense ministry said on Tuesday that a large Russian anti-ship missile launched from a bomber "highly likely" struck the apartment building.

The ministry says the Russian missile is "notoriously inaccurate when used against ground targets as its radar guidance system is poor at differentiating targets in urban areas." It also says evidence suggests "dysfunction of Russia's long-range strike capability is more profound."

Meanwhile, Russia's defense ministry announced on Tuesday that its minister Sergei Shoigu visited the headquarters of a unit in an area of operations.

The ministry said the headquarters is one of "Vostok," meaning "East" in Russian, but did not specify the location.

The ministry also released a video that shows Shoigu encouraging soldiers to do their utmost to celebrate the day of victory as soon as possible.