Four children were among at least 14 people injured in an overnight Russian air attack on the capital Kyiv, Ukrainian officials said.

Two high-rise residential buildings were hit in the strikes, Kyiv Mayor Vitali Klitschko said, without specifying if they were hit directly or as a result of falling debris.

"Everyone is receiving medical assistance, some have been hospitalised," Kyiv's military administration said in a post on Telegram.

Meanwhile, Russian air defences destroyed a drone heading towards Moscow, according to the city's mayor, Sergei Sobyanin.

The strikes come as US President Donald Trump said that he would only meet his Russian counterpart Vladimir Putin if he knew that "we're going to make a deal", days after plans for the two to .

"I've always had a great relationship with Vladimir Putin, but this has been very disappointing," Trump said on board Air Force One, as he began .

"I thought this would have gotten done before peace in the Middle East," he added.

Trump also said that he would like .

The US president is due to meet China's President Xi Jinping in South Korea on Thursday.

Ending the Russia-Ukraine war has become a focal point for Trump in recent months, with a ceasefire deal so far eluding him, despite his campaign promises to solve the situation quickly.

A summit with Putin in August failed to yield any tangible results, and Trump has grown increasingly frustrated with Moscow.

"Every time I speak to Vladimir, I have good conversations and then they don't go anywhere," Trump said earlier this week.

However, senior Russian envoy Kirill Dmitriev, who met US officials in Washington on Friday and Saturday, told CNN that he believed Russia, Ukraine and the US were close to a diplomatic solution to end the war.

"It's a big move by President Zelensky to already acknowledge that it's about battle lines," Dmitriev said, a reference to the Ukrainian president's description of using current front lines as the starting point for negotiations as a "good compromise".

"You know, his previous position was that Russia should leave completely so actually, I think we are reasonably close to a diplomatic solution that can be worked out," Dmitriev added.

Trump this week said that as he announced new sanctions targeting Russia's two largest oil companies - Rosneft and Lukoil.