KYIV, Ukraine (AP) -- Russian-installed authorities ordered all residents of the southern Ukrainian city of Kherson to leave "immediately" Saturday ahead of an expected advance by Ukrainian troops waging a counteroffensive to recapture the occupied area.
In a Telegram post, the regional pro-Kremlin administration called on civilians to use boat crossings over the Dnieper River to move deeper into Russian-held territory, citing a tense situation on the front and the threat of shelling and alleged "terror attacks" by Kyiv.
Kherson has been in Russian hands since the early days of the invasion in February. The city is the capital of a region of the same name, one of four Russian President Vladimir Putin illegally annexed last month.
The region's Kremlin-backed authorities previously announced plans to evacuate all Russian-appointed officials and as many as 60,000 civilians across the river, in what local leader Volodymyr Saldo said would be an "organized, gradual displacement."
Ukrainian officials have urged local residents to resist attempts to relocate them, with one local official alleging that Moscow wanted to take civilians hostage and use them as human shields.
Putin signed a decree Wednesday imposing martial law on Kherson and three other regions in southern and eastern Ukraine he declared as Russian territory in defiance of international law.
Elsewhere, hundreds of thousands of people in central and western Ukraine woke up on Saturday to power outages and periodic bursts of gunfire, as Ukrainian air defense tried to shoot down drones and incoming missiles.
Russia has intensified its strikes on power stations, water supply systems and other key infrastructure across the country, the latest phase of the war as it nears the eight-month mark.
Ukraine's air force said in a statement Saturday that Russia had launched "a massive missile attack" targeting "critical infrastructure," adding that it had shot down 18 out of 33 cruise missiles launched from the air and sea.
Air raid sirens blared across Ukraine twice by early afternoon, sending residents scurrying into shelters.
"Several rockets" targeting the capital were shot down on Saturday morning, Kyiv Mayor Vitali Klitschko said on the Telegram messaging service.
Similar reports were made by the governors of six western and central provinces, as well as the southern Odesa region on the Black Sea.
The presidential office said in its morning statement that five explosive-laden drones were downed in the central Cherkasy region southeast of Kyiv.
The western city of Khmelnytskyi, which straddles the Bug river and was home to some 275,000 people before the war, was left with no electricity, shortly after local media reported several loud explosions.
The city council urged local residents to store water, "in case it's also gone within an hour," in a social media post on Saturday.
The mayor of Lutsk, a city of 215,000 in Ukraine's far west, made a similar appeal on Telegram on Saturday. Power in Lutsk had been partially knocked out after Russian missiles slammed into local energy facilities, he said.
The central city of Uman, a key pilgrimage center for Hasidic Jews which counted some 100,000 residents before the war, was also plunged into darkness after a rocket hit a nearby power station, regional authorities said on Telegram.
In the capital and four surrounding regions, including Cherkasy, rolling blackouts came into effect on Saturday morning in response to the reduced power supplies. The state energy company Ukrenergo continued to urge all Ukrainians to conserve energy.
Earlier this week, President Volodymyr Zelenskyy called on consumers to curb their power use between 7 a.m. and 11 a.m. daily, and avoid using energy-guzzling appliances such as electric heaters.
Over the past two weeks, Moscow has increased its attacks on key civilian infrastructure across Ukraine. About 40% of the country's electric power system has been severely damaged, officials said. Zelenskyy said earlier in the week that 30% of Ukraine's power stations have been destroyed since Oct. 10.