A reported Russian attack on a city in eastern Ukraine that killed at least 16 people overshadowed a visit on Wednesday by US Secretary of State Antony Blinken to offer Kyiv support for its counteroffensive against Russia's invasion forces.
President Volodymyr Zelensky condemned the attack, which hit a market, shops and a pharmacy in the city of Kostiantynivka, close to the battlefield. He said a child was among the 16 or more dead, and many people were wounded.
"This Russian evil must be defeated as soon as possible," Zelensky said.
Blinken is expected to announce a new package of US wartime assistance worth more than $1 billion during his two-day visit, a senior State Department official said.
The first top US official to visit Kyiv since the counteroffensive began in early June, Biden had talks with Foreign Minister Dmytro Kuleba and was due to meet Zelensky.
"We want to make sure that Ukraine has what it needs, not only to succeed in the counteroffensive but has what it needs for the long term, to make sure that it has a strong deterrent," Blinken said standing alongside Kuleba.
US media reports have cited unidentified US officials as saying the Ukrainian counteroffensive has been too slow and hindered by poor tactics - criticism that angered Ukrainian officials and prompted Kuleba to tell critics to "shut up."
Ukraine has retaken more than a dozen villages and small settlements in its offensive. But its push into Russian-held territory has been slowed by minefields and trenches.
US officials have not publicly criticized Ukraine's military tactics, and last week said they had seen progress in the southeast.
The State Department official said Washington wanted to discuss how the counteroffensive was going and assess battlefield needs as well as any steps that might be required to shore up Ukraine's energy security before winter.
"I think what's most important is that we get a real assessment from the Ukrainians themselves," the official said. "We want to see, hear how they intend to push forward in the coming weeks."
Asked about Blinken's visit, Kremlin spokesman Dmitry Peskov said Moscow believed Washington planned to continue funding Ukraine's military "to wage this war to the last Ukrainian."
He said US aid to Kyiv would not affect the course of what he called Russia's special military operation.
Rising opposition to aid for Ukraine
Blinken's visit coincided with parliament approving the appointment of Rustem Umerov as defense minister following the dismissal of Oleksii Reznikov. Officials did not say whether Blinken would meet Umerov.
During his train ride to Kyiv, Blinken also held talks with Danish Prime Minister Mette Frederiksen, who was visiting the same day.
Blinken thanked Frederiksen for its donation of F-16 fighter jets to Ukraine and its leadership of a coalition of nations to train Ukrainian pilots, a State Department spokesperson said.
Denmark and the Netherlands announced last month they would supply more than 60 US-made F-16s as soon as pilots are trained to fly them - the first countries to offer the jets.
Zelensky thanked allies in a post on Telegram: "Thanks to courage. Thanks to unity. Thanks to weapons. Thanks to the support of the world."
The US government has so far provided more than $43 billion in weaponry and other military aid to Ukraine since the Russian invasion in February last year. A new package of security assistance is set to be announced this week, Reuters reported on Friday.
But several Republican presidential hopefuls have questioned US aid, fueling concerns over whether Washington will still back Ukraine at the same level once the US 2024 election campaign intensifies.