Russia on Saturday said it had captured six villages in Ukraine's east during a surprise ground offensive that prompted mass evacuations, as President Volodymyr Zelensky made an urgent call for military aid.
The Russian defence ministry said its troops had "liberated" five villages in Ukraine's Kharkiv region near the border with Russia -- Borysivka, Ogirtseve, Pletenivka, Pylna and Strilecha -- as "a result of offensive actions".
The village of Keramik in the Donetsk region was also now under Russian control, it said.
Ukrainian officials said that the country's forces were resisting but there was heavy fighting in the Kharkiv region near the border.
"Fighting for villages... continues in the border area", Ukrainian military spokesman Nazar Voloshyn said on national television, while "the enemy is currently localised".
There is "heavy fighting" in the border area and 1,775 people have been evacuated, Kharkiv regional governor Oleg Synegubov wrote on social media.
He insisted there was "no threat of a ground operation" for the city of Kharkiv, Ukraine's second largest.
At an arrival point for evacuees near Kharkiv, groups of people were arriving in vans and cars loaded with bags.
Evacuees -- many of them elderly -- received food and medical assistance in makeshift tents.
One 61-year-old woman, Lyubov Nikolaieva, told AFP she had fled the border village of Lyptsi along with her 81-year-old mother.
"It's impossible to live there," said Nikolaieva, adding that her family "stayed there until the last moment".
"There is constant incoming fire: those guided aerial bombs and mortar shells whistling overhead. It became very scary," she said.
- 'Saves lives' -
The Kharkiv region has been mostly under Ukrainian control since September 2022.
Ukrainian President Volodymyr Zelensky said troops must "return the initiative to Ukraine" and urged Kyiv's allies to speed up arms deliveries.
"Every air defence system, every anti-missile system is literally what saves lives," Zelensky said.
"It is important that our partners support our soldiers and Ukrainian resilience with timely deliveries -- really timely ones," he stressed.
"The package that really helps is the weapons brought to Ukraine, not just the announced ones."
Ukrainian forces have multiplied attacks inside Russia and Russia-held areas of Ukraine, particularly on energy infrastructure.
On Saturday a missile strike hit a restaurant called Paradise in the city of Donetsk, eastern Ukraine.
The attack using US HIMARS precision rocket launchers killed three civilians -- two diners and a restaurant member of staff -- and wounded eight, the head of the region's Russian-backed administration, Denis Pushilin, said.
Moscow-installed authorities in the Russian-occupied Lugansk region in eastern Ukraine said four people were killed by a Ukrainian strike with US-made missiles on an oil depot in Rovenky.
Governor Leonid Pasechnik said the strike "enveloped the oil depot in fire and damaged surrounding homes".
In Russia, two people were reported killed by Ukrainian strikes in the Belgorod and Kursk regions.
Ukrainian officials also reported a total of six civilians killed in Russian shelling in the Donetsk, Kharkiv and Kherson regions over the past day.
'Tactically significant gains'
Officials in Kyiv had warned for weeks that Moscow might try to attack its northeastern border regions, pressing its advantage as Ukraine struggles with delays in Western aid and manpower shortages.
Ukraine's military said it had deployed more troops.
"Reserve units have been deployed to strengthen the defence in these areas of the front," it said.
Military expert Olivier Kempf told AFP Saturday that Russia's ground operation was most likely aimed at creating a buffer zone near its Belgorod region, recently raided by pro-Ukrainian units, or diverting Ukraine's resources from the Donetsk region.
"Twenty-four hours after the launch of the operations, it doesn't look like a big offensive," said the associate fellow at the Foundation for Strategic Research, a French think tank.
Washington announced a new $400 million military aid package for Kyiv hours after the offensive began, and said it was confident Ukraine could repel any fresh Russian campaign.