A child is among at least four people that have been killed in their homes by a Russian cruise missile aiming for a nearby air base.
The tragedy happened in the Ukrainian city of Zhytomyr where a government adviser said a missile had struck, having been intended for an air base.
Anton Gerashchenko, adviser to the Ukrainian interior minister, told of the tragedy in the latest bombings on his Telegram channel, on Tuesday.
He said the residential buildings near the base of the 95th Airborne Brigade in Zhytomyr, 75 miles west of the capital Kyiv, had been set on ablaze by the cruise missile.
"So far, four people have died. Including a child," he said.
Moscow warned residents of the capital Kyiv on Tuesday to flee their homes and rained rockets on Ukraine's second city, Kharkiv, as Russian commanders intensified their bombardment of urban areas in a shift of tactics after their six-day assault stalled.
Ukrainian Health Minister Viktor Lyashko wrote on Facebook that Russian forces had killed a paediatric anaesthesiologist, firing at her car as she was driving her wounded nephew to the hospital from the village of Kukhari, in the Kyiv region.
Ukraine's defence ministry said a total of 16 high-precision guided missiles had been fired on Monday, between 7pm and 8pm local time at residential areas of Kharkiv from a strategic bomber flying over Russia's Belgorod region.
"High-rise buildings, schools, kindergartens and other infrastructure of the city were destroyed," the ministry said on its Facebook page.
"According to preliminary data, dozens of Kharkiv residents, including children, died from these airstrikes.
"Unfortunately, in the current situation, it is extremely difficult for the air force to cover the sky in this region, because part of the country's air defence system was destroyed by Russian ballistic and cruise missile strikes."
In the largely Russian-speaking city of Donetsk, in territory controlled by Russian-backed separatists, local authorities said three civilians had been killed by Ukrainian shelling.
The self-declared Donetsk People's Republic, recognised as independent by Moscow last week, was one of the transit points used by Russian forces that invaded Ukraine on February 24.
Meanwhile, Ukraine's Defence Ministry says it has evidence that Belarus, a Russian ally, is preparing to send troops into Ukraine.
The ministry statement, posted on Facebook at midnight, said the Belarussian troops have been brought into combat readiness and are concentrated close to Ukraine's northern border.
"During the past 24 hours, according to intelligence findings, there has been significant aircraft activity. In addition, there has been movement of a column of vehicles with food and ammunition approaching the border," the statement said.
