Ukraine's advance in the Kharkiv region has been "very sharp and rapid" and Ukrainian forces have recaptured a number of settlements, the Russian-installed administrator of Russian-controlled parts of the region said in a live online broadcast.
"The enemy is being delayed as much as possible, but several settlements have already come under the control of Ukrainian armed formations," Vitaly Ganchev, head of the Russian-backed administration in Kharkiv region, said on state television host Vladimir Solovyov's daily livestream.
At least 10 people were wounded when the center of Ukraine's second city, Kharkiv, was hit by Russian rocket fire on Friday, local officials said, while the president's top aide said the attacks were revenge for Ukrainian success on the battlefield.
Rockets hit a children's arts center and a school, as well as private homes, wounding at least ten people, including three children, Kharkiv mayor Ihor Terekhov wrote on Telegram.
What provoked the attack?
Ukraine's presidential chief of staff Andriy Yermak said the attack was revenge for the success of Ukraine's armed forces, an apparent reference to a recent counter-attack in nearby areas which Ukraine says led to the recapture of over 20 settlements.
"For every success of Ukraine's armed forces, for every victory, Russians... answer with strikes on innocent people," Yermak wrote on Telegram, confirming that children were among the wounded.
"Russia is a terrorist state... you will answer (for this), and you almost certainly won't be able to hide anywhere," he wrote.
"For every success of Ukraine's armed forces, for every victory, Russians... answer with strikes on innocent people."
Andriy Yermak
It was not immediately possible for Reuters to verify the reports. Russia denies targeting civilians.
After Kyiv visit, Blinken meets US allies in Brussels in bid to maintain unity
US Secretary of State Antony Blinken was in Brussels on Friday after a visit to Kyiv, as Washington seeks to strengthen unity as Europe faces a winter of raised energy costs.
Blinken met NATO Secretary General Jens Stoltenberg and ambassadors from the alliance, in part to report back from his trip, on which he pledged new military aid and was briefed on Ukraine's counteroffensive against Russian forces.
A senior State Department official said ahead of the visit to Brussels that it was part of the "constant gardening" the Biden administration has been doing to maintain unity among European nations.
Some analysts say the shortages and a surge in living costs as winter approaches risk sapping Western support for Kyiv as governments try to deal with disgruntled populations.
"President Putin thought that he could divide and weaken NATO. Today, the alliance is stronger, more unified and better resourced that ever before," Blinken said at a news conference following the meetings.
Stoltenberg said pressure on energy supplies and the soaring cost of living would test "our unity and solidarity."
"But the price we pay is measured in money, while the price Ukrainians are paying is measured in lives, lost lives every day," he said.