Some Russian military units suffering heavy losses in Ukraine have been forced to return home or to Belarus to resupply, placing additional pressure on Russia’s already strained logistics, the British Defense Ministry said in an assessment Wednesday.

The problems demonstrate the difficulties Russia is having reorganizing its units in forward areas within Ukraine, the assessment says. Moscow will likely continue to compensate for its reduced ground-force capability “through mass artillery and missile strikes,” the assessment says.

President Joe Biden also spoke with Ukraine President Volodymyr Zelenskyy on Wednesday, informing him the United States intends to provide the Ukrainian government with another $500 million in aid, the White House said.

Russia this week announced plans to dial back its military activity in and around Kyiv, but Ukraine authorities say the city continues to be battered by artillery assaults. Russian military leaders have said forces would focus on “liberating” the breakaway Luhansk and Donetsk territories in the Donbas region of eastern Ukraine.

“Russia’s stated focus on an offensive in Donetsk and Luhansk is likely a tacit admission that it is struggling to sustain more than one significant axis of advance,” the British assessment says.

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Latest developments

►Defense Secretary Lloyd Austin and Army Gen. Mark Milley, chairman of the Joint Chiefs of Staff, have reached out to their Russian counterparts who have “not answered and they have not replied with a willingness to do so,” Pentagon spokesman John Kirby said.

►Poland announced steps to end all Russian oil imports by year’s end. Earlier this week Poland banned coal imports.

►Over 4 million refugees have now fled Ukraine, about 10% of the population, a United Nations refugee agency says.

►No significant breakthrough took place in peace talks with Ukraine, Kremlin spokesman Dmitry Peskov said Wednesday.

►Ukraine asked Norway for long-range weapons to protect Ukraine’s battered cities.

Biden pledges $500 million more worth of aid in call with Zelenskyy

President Joe Biden pledged an additional $500 million in aid to Ukraine in a phone call Wednesday with President Volodymyr Zelenskyy as peace talks between Russia and Ukraine have failed to produce a breakthrough.

The White House confirmed the additional “direct budgetary aid” after Biden spoke to Zelenskyy for about an hour in a call that concluded shortly after noon ET. The infusion of new assistance is on top of $2 billion the U.S. has committed to Ukraine since Biden became president.