KYIV, Ukraine (AP) -- Russia's military leadership has withdrawn its officers in the Russian-annexed city of Kherson across the Dnieper River in anticipation of an advance of Ukrainian troops, the Institute for the Study of War think tank said Sunday.
To delay the Ukrainian counteroffensive as the Russians complete their retreat, Moscow has left newly mobilized, inexperienced forces on the other side of the wide river, it added.
The troop movements come as the Ukrainian military said its forces have continued their counteroffensives in the Kherson and Zaporizhzhia regions.
On Saturday, Russian-installed authorities in Ukraine told all Kherson residents to leave immediately ahead of the expected action by Ukrainian troops to take back the city.
Kherson has been in Russian hands since the early days of the eight-month-long war in Ukraine. The city is the capital of a region of the same name, one of four that Russian President Vladimir Putin illegally annexed last month and put under Russian martial law on Thursday.
On Friday, Ukrainian forces bombarded Russian positions across the province, targeting pro-Kremlin forces' resupply routes across the Dnieper River and preparing for a final push to reclaim the city.
The ISW think tank also said Sunday that Russia's latest war strategy of targeting power plants in recent days appears to be aimed at diminishing Ukrainians' will to fight and forcing Ukraine's government to spend additional resources to protect civilians and energy infrastructure. It said the effort was unlikely to damage Ukrainian morale but would have significant economic impact.
The Ukrainian military said Sunday that Russian forces are now mostly on the defensive, but are keeping up offensive attacks on Ukraine's energy infrastructure and on several towns in the eastern Donbas area.
Nine regions across Ukraine, from Odesa in the southwest to Kharkiv in the northeast, saw attacks again targeting energy and other critical infrastructure over the past day, the Ukrainian general staff said. It reported a total of 25 Russian air strikes and more than 100 missile and artillery strikes around Ukraine.
Ukrainian counteroffensive forces in the Kherson and Zaporizhzhia regions, meanwhile, targeted Russian-held facilities, notably in the town of Nova Kakhovka, and carried out 17 air strikes in the overall campaign, according to the Ukrainian general staff.
In a Telegram post Sunday, the Ukrainian military claimed to have destroyed 14 Iranian-made Russian drones over the past day.
Russian S-300 missile strikes overnight hit a residential neighborhood in the city of Mykolaiv, injuring three people, according to the Ukrainian military's southern command. Two apartment buildings, a playground and a warehouse were damaged or destroyed, it said in a Facebook post. The reports could not be immediately verified.
Elsewhere, Ukraine's security service said Sunday it has detained the longtime chief of a major aircraft engine factory, accusing him of collaborating with Russia by supplying military equipment for Russian attack aircraft.
Viacheslav Bohuslaiev, president of the Motor Sich plant in Zaporizhzhia, and another top factory official were charged with collaboration and "assisting the aggressor state."
The Ukrainian security service SBU said in a statement that the two are accused of colluding with a Russian arms maker close to the Kremlin to supply Ukrainian-made engines and spare parts to Russian forces. The SBU described a complex scheme using intermediaries in three countries to evade sanctions against Russia.
Motor Sich is one of Ukraine's leading manufacturers and has been a key maker of aircraft engines since Soviet times. Its facilities have been repeatedly targeted by Russian strikes during the war. Engines made by Motor Sich were used to equip Russian helicopters before supplies were halted following Russia's 2014 annexation of Ukraine's Crimean Peninsula.