The latest assault included more drones in a single night than Russia used in the entire month of July last year.

One of those key frontline areas is Pokrovsk, a strategic hub in eastern Ukraine, which Moscow has been trying to capture for more than two years. According to the head of Ukraine's army Gen Oleksandr Syrskyi, Russia has concentrated some 111,000 troops in that area.

Ukrainian officials say Russia has fired more than 700 attack and decoy drones at Ukraine overnight. That tops previous nightly barrages for the third time in two weeks.

There is too little data to generate a comparable live estimate for Ukraine. However, a catalogue of the known dead and missing from UAL osses, a website, implies that between 73,000 and 140,000 Ukrainian soldiers have died since the invasion began.

Facing a numerically superior foe, Ukraine is under pressure to replenish its ranks on the battlefield where, after three years of war, recruitment is already a challenge.

The Strasbourg-based European Court of Human Rights said Russia had performed indiscriminate military attacks, summary executions of civilians, torture including the use of rape as a weapon of war, unjustified displacement and transfer of civilians and other violations.

Russia launched its largest drone and missile bombardment of Ukraine overnight into Wednesday, according to Ukrainian President Volodymyr Zelenskyy.

Europe's top human rights court ruled that Russia was responsible for widespread violations of international law in Ukraine, including the downing of Malaysia Airlines Flight 17 in 2014, marking the first time an international court has held Moscow accountable for human rights abuses related to the conflict there.

A five-year-old boy died of burns sustained in a Ukrainian drone strike on a beach in the Russian city of Kursk, regional Governor Alexander Khinshtein said on Telegram, raising the death toll in the attack to four, including a member of Russia’s National Guard.