Two children were among three killed in a Russian bombardment of an apartment building in Ukraine's city of Kharkiv, with dozens more injured.

A guided aerial bomb — a powerful weapon widely used by Russia — hit the building in the north-eastern city on Wednesday evening local time, according to Ukrainian President Volodymyr Zelenskyy.

The attack killed three — two boys aged 12 and 15 and a man — and injured 35 people, local governor Oleg Synegubov said on Thursday, upping earlier tolls.

"The body of a 15-year-old boy with no signs of life was extracted from the rubble of the destroyed part of the nine-storey building," Mr Synegubov said in his latest update.

Rescuers struggled to remove the body of the boy — who lived with his grandparents on the first floor of the building — after several floors collapsed, a spokesperson for the prosecutor's office said.

Earlier, Mr Synegubov said at least 29 people were wounded in the attack.

Mr Syniehubov said on the Telegram messaging app that the strike had triggered a fire and destroyed most of one entrance, making a huge hole in the building.

President Volodymyr Zelenskyy said the attack underscored the need for more military aid from Ukraine's Western allies.

"Our partners can see what is happening every day," he wrote on Telegram.

"And in these conditions, every decision that is put off means, at the very least, dozens of lives and hundreds of Russian bombs used against Ukraine."

Kharkiv, Ukraine's second largest city, has remained in Ukrainian hands through the initial failed advance of Russian forces on the capital Kyiv in the early days of the February 2022 invasion.

It has since become a frequent target of Russian air attacks.

Russian forces close in on Kharkiv, Odesa, Donetsk

Russian forces have taken control of the settlement of Kruhliakivka, near the key town of Kupiansk in the Kharkiv region, the Russian Defence Ministry said on Wednesday.

Ukraine's military made no acknowledgement of Kruhliakivka falling into Russian hands, but officials said fighting was heavy in the area and the city of Kupiansk had come under Russian shelling.

Ukraine's General Staff listed Kruhliakivka as one of nine villages gripped by fighting, with 15 Russian attacks repelled and nine clashes still going on.

The defence ministry also said Russian forces captured the Yasna Poliana settlement in the Donetsk region of eastern Ukraine, RIA Novosti news agency reported on Thursday.

The Ukrainian military reported fighting in Odesa on Thursday, with Russian forces having launched two ballistic missiles and eight guided missiles to capture a strategic bridge across the Bilhorod-Dnistrovskyi Estuary overnight.

The bridge is an important railway and car connection in the region and has been a target several times since Russia's February 2022 invasion.

It was unclear whether it had been damaged in the latest strike.

Russian forces also used two ballistic missiles to attack the eastern town of Kramatorsk, the Ukrainian military said.

Russian forces have continued their steady push westward through eastern Ukrainian sections of the 1,000-kilometre front line.

North Korea launches ballistic missile test after soldiers reported in Kursk

North Korea fired a long-range ballistic missile into the sea off its east coast on Thursday, South Korea and Japan said.

The launch was reported from an area near the North's capital, Pyongyang, at 7:10am local time, the Joint Chiefs said in a statement.

The Japanese government later said the missile dropped into the sea at 8:37am, local time.

"It is believed the North Korea ballistic missile is a long-range ballistic missile fired at a high angle," the Joint Chiefs of Staff said in a statement.

Japanese Prime Minister Shigeru Ishiba later said there had been no reported damage from the launch.

Defence Minister Gen Nakatani said Japan strongly condemns the North's action, which threatened not only Japan but also the international community.

He said the flight time was likely the longest of North Korean missile launches and could be a new type of missile.

The launch follows reports from South Korea and the United States that North Korea had dispatched 11,000 troops to Russia for deployment in the war in Ukraine, with 3,000 of them already moved close to the front lines.

North Korea has already been supplying arms to Russia including missiles, artillery and anti-tank rockets in more than 13,000 containers since August last year, according to the South's intelligence agency.

Ukraine authorities have also said some of missiles fired by Russia were from the North.

Reuters/AFP