A Russian missile strike killed 47 people and injured another 206 in the Ukrainian city of Poltava on Tuesday, according to the country's first lady, making it the war's deadliest single attack so far this year.

Earlier, in a video posted on Telegram, Ukrainian President Volodymyr Zelenskyy said two ballistic missiles had hit the city, which is located about 110 kilometres from the border with Russia and about 350 kilometres south-east of Kyiv.

"One of the buildings of the [Poltava Military] Institute of Communications was partially destroyed. People found themselves under the rubble. Many were saved," Mr Zelenskyy said.

He also said a nearby hospital was damaged in the attack.

Ukraine's defence ministry described the strike as "barbaric", and said the missiles hit shortly after an air raid alert sounded, meaning many people were on their way to a bomb shelter.

Photographs posted on social media in Ukraine showed several bodies lying on the ground covered in dust and debris, with the badly damaged side of a large building behind them.

The Reuters news agency could not immediately verify the images, and Russia has not yet commented on the attack.

Mr Zelenskyy has ordered a full and prompt investigation into the incident.

The defence ministry went on to say rescue crews and medics had been able to save 25 people after the attack, with 11 of those having been dug out from underneath rubble.

Poltava governor Filip Pronin announced three days of mourning following the attack, and said that many residents had donated blood for the injured.

The identities of those killed in the strike were not immediately disclosed.

Speaking after the attack, Mr Zelenskyy repeated his calls for more Western air defences and urged allies to allow their long-range weapons to be used for strikes deeper into Russian territory in order to protect Ukraine.

"We keep telling everyone in the world who has the power to stop this terror: Air defence systems and missiles are needed in Ukraine, not in a warehouse somewhere," he said.

"Long-range strikes that can protect us from Russian terror are needed now, not some time later. Unfortunately, every day of delay means loss of life."

Russia has intensified its missile and drone attacks on Ukraine in recent weeks, two-and-a-half years into the full-scale war sparked by Russia's invasion of its smaller neighbour in February 2022.

Last week Ukraine was pummelled with the heaviest bombardment to date, and on Monday ballistic and cruise missiles targeted Kyiv, causing loud explosions.

Ukraine also targeted Russia with more than 158 drones over the weekend, damaging an oil refinery near Moscow and a power station.

Reuters/AP/ABC