Ukrainian President Volodymyr Zelensky on Saturday called for more sanctions against Russia as overnight strikes killed at least 14 people and wounded dozens more, days ahead of talks between US and Ukrainian negotiators aimed at securing a truce.

A Russian assault hit the centre of Dobropillia in Ukraine's eastern Donetsk region late on Friday, killing 11 people and wounding 30, according to the emergency services. 

Separately, three people were killed and seven others wounded in a drone attack early on Saturday in the city of Bogodukhiv, the military head of the eastern Kharkiv region, Oleg Synegubov, said.

Russia fired two missiles and 145 drones at Bogodukhiv, Ukraine's air force said.

The overnight air raids came after US President Donald Trump threatened new sanctions and tariffs on Russia but said it may be "easier" to work with Moscow than Kyiv on efforts to end the three-year-long war.

"Such strikes show that Russia's goals are unchanged. Therefore, it is very important to continue to do everything to protect life, strengthen our air defense, and increase sanctions against Russia," Zelensky wrote on the Telegram social media channel.

In Dobropillia, AFP saw charred residential buildings, flattened market stalls and evidence of cluster bomb damage.

Irina Kostenko, 59, spent the night cowering in her hallway with her husband. When she left the apartment building on Saturday, she saw a neighbor "lying dead on the ground, covered with a blanket".

"It was shocking, I don't have the words to describe it," Kostenko told AFP.

Zelensky said that Russia had struck Dobropillia, waited until rescuers arrived and then "deliberately" targeted them as well.

"This is a despicable and inhumane tactic of intimidation that the Russians often use," he said.

Trump sanctions threat

US and Ukrainian negotiators are due to meet in Saudi Arabia next week with bilateral relations frayed.

Trump publicly berated Zelensky during a White House meeting and suspended US aid to Kyiv in a stated bid to encourage diplomacy.

"I'm finding it more difficult frankly to deal with Ukraine and they don't have the cards," Trump said on Friday. "It may be easier dealing with Russia."

The remarks followed Trump on Friday threatening new sanctions and tariffs on Russia over its bombardments of Ukraine.

"To Russia and Ukraine, get to the table right now, before it is too late," he added.

Zelensky is due to land in Saudi Arabia on Monday for talks with Crown Prince Mohammed bin Salman.

The meeting is a day before Ukrainian officials are expected to hold fresh talks with their US counterparts on Tuesday there.

On Saturday, Russia said it had retaken three villages in its Kursk region previously captured by Ukraine.

The Russian defence ministry announced the recapture of Viktorovka, Nikolayevka and Staraya Sorochina. 

Ukrainian soldiers launched an offensive in Kursk last summer but Russia has wrested back control of more than two-thirds of the territory captured by Kyiv.

Moscow's defence ministry on Saturday said its air defence systems destroyed 31 Ukrainian drones over the past night.

A Ukrainian drone attack also targeted Russia's Kirishi oil refinery, with air defence forces shooting down one drone on approach and another over the facility, Leningrad governor Aleksandr Drozdenko said, adding that the "external structure of one of the reservoirs was damaged by falling debris".

A civilian was wounded by a drone attack in Belgorod district near the Ukraine border, local governor Vyacheslav Gladkov wrote on Telegram.