As many as 15,000 Russian troops have been killed since the invasion of Ukraine began four weeks ago, according to NATO’s first estimate.

Russia has suffered 30,000 to 40,000 battlefield casualties, including 7,000 to 15,000 killed, a senior NATO military officer said in a briefing Wednesday from the alliance’s military headquarters in Belgium. 

Secretary of State Antony Blinken also said Wednesday that the U.S. has determined Russian military forces have committed war crimes in Ukraine.

The senior military officer, speaking on condition of anonymity under ground rules set by NATO, said the estimated deaths are based on information from the Ukrainian government, indications from Russia and open-source information. The officer said the number of fatalities came from a calculation of three wounded soldiers for every soldier killed. Casualties include killed, wounded or missing in action as well as those taken prisoner.

Earlier this week, a senior Pentagon official estimated the Russian military had lost more than 10% of the combat force in Ukraine. 

Ukraine’s military, staggered in the early days of the war by the brutal fury of Russia’s invasion, has gained footing and begun the arduous task of taking back territory overrun by Russia’s initial onslaught.

The Ukraine Defense Ministry claims its forces have driven occupying Russian troops out of Makariv – a small Kyiv suburb that’s crucial because it provides control of a highway to the west. The effort also blocked Russian troops from surrounding Kyiv from the northwest and provided the Ukrainian military with a much-needed success story.

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An assessment released Wednesday by the British Defense Ministry described the battlefield across northern Ukraine as “largely static.”  Russian forces are likely reorganizing before resuming large-scale offensive operations, the ministry said in a tweet.

President Joe Biden embarked Wednesday on a multi-day trip to Europe, where he’ll talk with allies about the ongoing response to Russia’s invasion, including military assistance for Ukraine and new sanctions on Russia. Jake Sullivan, Biden’s national security adviser, said the president is working on long-term efforts to boost defenses in Eastern Europe and reduce the continent’s reliance on Russian energy.

Latest developments

►Dancers who have fled Ukraine – and Russia – because of the war have found a temporary home in Berlin’s top ballet company, State Ballet, which helps with practice space, housing and even shoes.

►Putin aide Anatoly Chubais resigned, left Russia because of the war and has no intention of returning, according to multiple media outlets. Chubais, a special envoy for ties with international organizations, is the highest-profile figure to step down since the war began, Reuters reports.