Ukrainian President Volodymyr Zelensky has cancelled all trips abroad in the coming days in light of the Russian offensive in the Kharkiv region, his spokesman Serhiy Nykyforov said on Wednesday.
Zelensky was to visit Spain and Portugal at the end of the week.
Russia began a ground and air assault on Ukraine's second city of Kharkiv, in the north-east, and the surrounding region last week.
In what analysts describe as one of the most perilous moments for Kiev in the war, Moscow's forces have been able to capture several villages as they continue to bombard Kharkiv with missiles.
Worries are mounting that Russia is using the wave of attacks on the city to possibly lay the groundwork to capture Kharkiv.
The military leadership in Kiev - struggling with a lack of weapons, ammunition and soldiers - said earlier on Wednesday that troops were being withdrawn from some Kharkiv positions.
"As a result of combat and offensive actions by the enemy, our units carried out a manoeuvre at certain sections in the Lukyantsi and Vovchansk areas and moved to more advantageous positions in order to save the lives of our soldiers and avoid casualties," the Ukrainian general staff announced on Facebook overnight.
Russia claims capture of symbolic Ukrainian village
The Russian military said later on Wednesday it had recaptured the village of Robotyne in south-eastern Ukraine.
"Units of the Dnepr Army Group have completely liberated the village of Robotyne in the Zaporizhzhya region," the Ministry of Defence in Moscow said in its latest situation report.
Kiev has not yet commented on the alleged loss of Robotyne. It was not possible to independently verify the claim.
Robotyne was first captured by Moscow-allied troops shortly after the start of the full-scale Russian invasion of Ukraine in February 2022.
All that remains of the village are ruins, but it has great symbolic significance for Ukraine. During Kiev's ultimately failed summer offensive in 2023, Robotyne was the only village in the section of the front that the Ukrainians were able to liberate
US aid package on the way
The dramatic situation around Kharkiv comes at the same time as a visit by US Secretary of State Antony Blinken.
Blinken announced in Kiev on Wednesday that the United States is providing Ukraine with another $2 billion in military aid for its defence against the Russian invasion.
"We will provide an additional $2 billion in foreign military financing for Ukraine," Blinken, who arrived in the Ukrainian capital on Tuesday, said.
The visit is Blinken's fourth since the start of the war in February 2022 and is also the first visit since the US Congress approved a long-delayed aid package of $61 billion in April.
Ukraine has been on the defensive for months due to a lack of weapons, ammunition and soldiers.
Putin calls for arms manufacturing push
Russian President Vladimir Putin has called for a significant increase in the pace of arms production, over two years into the war against Ukraine.
"We must double and triple our efforts in this direction," he said on Wednesday at a meeting with representatives of the defence industry.
Only by introducing state-of-the-art weapons systems as quickly as possible could Russia succeed in staying one step ahead of Ukraine in the war, he said.
Russia says US-made missiles shot down
Russia's air defences have shot down 10 US-made ATACMS missiles over the annexed Black Sea peninsula of Crimea overnight, the Defence Ministry in Moscow said on Wednesday morning.
It was not possible to independently verify the claim.
The Defence Ministry also reported that 17 Ukrainian drones and other projectiles were shot down over the Russian border regions of Belgorod, Kursk and Bryansk.
