The Russian General Staff said on Friday that 1,351 Russian troops have died and another 3,825 injured in Ukraine, where a fierce resistance by soldiers and non-professional fighters have frustrated Moscow's attempt at a swift victory.
The figures are the first official casualty tolls issued by Moscow since the beginning of March, when the number of Russian dead was given as 498.
The latest claim could not be independently verified and does not appear to include Moscow-backed separatists.
Analysts believe that the Russian military has in reality lost thousands of troops in the month-old conflict. A senior NATO official told the Wall Street Journal on Thursday that the Western alliance estimates between 7,000 and 15,000 Russian soldiers have been killed.
Kiev said on Friday that 135 children had been killed in Ukraine since the Russian invasion began, with a further 180 children having been injured, mostly in the Kiev, Kharkiv and Donetsk regions.
The Ukrainian Prosecutor General's Office also announced on Friday that over 560 Ukrainian educational institutions had been damaged in Russian strikes, over 70 of which were totally destroyed, it said.
Fuel depot destroyed
The announcement coincided with Russian forces saying they had destroyed one of Ukraine's largest fuel depots in the village of Kalynivka, near Kiev. The depot was shelled with Kalibr cruise missiles late on Thursday, according to Russian Defence Ministry spokesperson Igor Konashenkov.
As attacks on Ukraine's critical infrastructure continued, the CEO of the country's largest energy supplier Naftogaz, Yuriy Vitrenko, told Germany's Zeit newspaper that there were now around 300,000 households in Ukraine without gas and heating.
Despite the devastation, Britain's Ministry of Defence reported that Ukrainian forces had been able to re-occupy towns up to 35 kilometres east of Kiev, adding that Ukrainian forces were "likely to continue to attempt to push Russian forces back" towards Hostomel Airfield north west of Kiev.
The ministry said that "logistic issues and Ukrainian resistence" were also slowing down Russian attempts to circumvent the southern city of Mykolaiv as they attempted to push towards the key port city of Odessa.
Russian military units elsewhere in Ukraine were reported to have begun withdrawing from some areas after suffering heavy losses, the Ukrainian military said in a situation report released early on Friday.
Heavy losses
Some Russian units even withdrew behind the Russian border after losing more than half of their personnel, the Ukrainian General Staff said.
Meanwhile, reports of a possible fresh outbreak of shelling near the former Chernobyl nuclear power plant were also raised as a cause for concern on Friday.
The director general of the International Atomic Energy Agency (IAEA), Rafael Grossi, said that Russian forces fired on Ukrainian checkpoints in the nearby city of Slavutych, citing information from the Ukrainian nuclear regulatory authority.
The violence put "the homes and families of the operating staff who guarantee nuclear and radioactive safety" at the former nuclear power plant in danger, Grossi said.
The United Nations said that it was still investigating alleged Russian war crimes in Ukraine, but that it was not yet ready to make a final assessment. Among the claims being investigated by the UN are the deployment of illegal phosphate bombs and cluster munitions.
