The United States on Wednesday promised to send more precision rocket systems to Kyiv, soon after Moscow signaled it was aiming to seize more Ukrainian territory beyond the eastern industrial region of Donbas.
The announcement came as the European Commission called on EU members to slash demand for natural gas to relieve dependence on Russian energy and the bloc agreed an embargo on Russian gold imports, measures that Kyiv nevertheless dismissed as insufficient.
Pentagon chief Lloyd Austin said Washington would send four more M142 High Mobility Artillery Rocket System (Himars), which have notably boosted Kyiv's capabilities on the battlefield in recent weeks by allowing Ukrainian forces to hit Russian targets from long distances.
"Ukraine needs the firepower and the ammunition to withstand this barrage and to strike back," Austin told reporters, adding that the new shipment would bring the total of US Himars sent to Kyiv to 16.
Hours earlier, Russian Foreign Minister Sergei Lavrov said in an interview that Moscow's military was no longer only focused on wresting control of the east Ukraine regions of Lugansk and Donetsk, which have been partially controlled by pro-Moscow rebels for years.
"The geography is different now. It is not only about the DNR and LNR, but also the Kherson region, the Zaporizhzhia region and a number of other territories," he explained to state media.
On Tuesday, the United States said Russia was "beginning to roll out a version of what you could call an annexation playbook" -- citing the same areas mentioned by Lavrov.
Russian forces, since invading Ukraine on February 24, have steadily advanced into each of those regions, wreaking destruction as they captured key cities and met fierce Ukrainian resistance.
In recent weeks, they have also hit Ukrainian civilian targets in cities and towns far away from the frontline, leaving scores of civilians dead, in what Ukrainian President Volodymyr Zelensky has called a terror campaign.
In an emotional speech before the US Congress on Wednesday, Ukrainian First Lady Olena Zelenska described the suffering of millions of Ukrainian parents and children, and asked Washington for air-defense systems to fend off Russian missiles.
Zelenska, stepping into a more public role after staying sheltered in the first weeks of the war, displayed images of children who were killed or maimed by Russia, including a four-year-old killed by a strike in the city of Vinnytsia.
Photos of her blood-spattered pink stroller and footage of her final moments went viral on social media.
"Help us to stop this terror against Ukrainians," Zelenska said.
Later in the day, Zelensky expressed hope that Kyiv's pleas for anti-missile systems would be heard, saying: " I hope the answers to our requests won't be long in coming."
The steady progress of Russian troops in the east has come after Moscow's forces failed early in the invasion to capture the capital Kyiv and were pushed back from Ukraine's second city Kharkiv.
But Russian artillery has pursued an almost constant shelling campaign on Kharkiv, and strikes on Wednesday killed three people, local officials said.
"There was a 13-year-old boy among them," the regional governor Oleg Synegubov said in a statement on social media.
AFP journalists saw a man in shock kneeling over the body, which was covered by a blue sweatshirt and surrounded by shards of broken glass.
While the brunt of recent fighting in Ukraine has focused on Donbas, a Ukrainian counter-offensive in the south has slowly clawed back some Russian-held territory, thanks in large part to Western-supplied long-range artillery.
Lavrov said that Western arms deliveries to Ukraine had been a factor in Moscow's decision to focus beyond the east and said its ambitions could expand even more if the shipments continued.
"We cannot allow the part of Ukraine that Zelensky will control or whoever replaces him to have weapons that will pose a direct threat to our territory and the territory of those republics that have declared their independence," Lavrov said, referring to Donetsk and Lugansk.
Lavrov also dismissed the idea of further peace talks with Ukraine, claiming that earlier rounds showed Kyiv was unwilling to negotiate in "earnest".
"It doesn't make any sense in the current situation," he told state media.
Russian and Ukrainian delegations are nevertheless expected in Istanbul in the coming days for more talks on unblocking Ukraine's Black Sea grain exports.
Turkish President Recep Tayyip Erdogan said Wednesday he hoped an agreement could be formulated "this week".
The West has responded to Russia's invasion with several packages of damaging sanctions, which in turn has seen Russia cut natural gas supplies to the bloc, spurring a supply and cost crisis.
In its latest package of penalties Wednesday, the EU targeted gold exports and froze assets at Russia's largest bank Sberbank.
And Brussels also asked EU members to reduce demand for natural gas by 15 percent in order to limit supplies from Russia, which last year accounted for 40 percent of EU's imports.
Zelensky however criticized those measures as inadequate, saying in his address: "Russia must pay a much higher price for this war, which would force it to seek peace."