Donald Trump has said he would like China's help to deal with Russia as he seeks to bring an end to the war in Ukraine.

I'd like China to help us out with Russia, the US president said on board Air Force One, as he flew to Asia for a whirlwind tour, where he will meet China's Xi Jinping in South Korea.

It could be wishful thinking, however. China is Russia's biggest ally, and a vital support to Moscow since Western sanctions were imposed over its war in Ukraine.

Trump's comments come off the back of a difficult week for Kyiv - the US refused to give it Tomahawk cruise missiles, EU leaders did not release frozen Russian cash to help fund its defense, and there have been more deadly strikes.

Ending the Russia-Ukraine war has become a focal point for Trump in recent months, with a ceasefire deal eluding him so far despite his campaign promises to solve the situation quickly. A summit with Putin in August provided no 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.

On Wednesday, he announced new sanctions against Russia's two biggest oil companies - the first direct interventions the Trump administration has imposed on Russia over the war. However, the Kremlin has claimed it was immune to the sanctions.

While Trump's meeting with Xi on Thursday is expected to focus on the trade relations between the US and China, Trump indicated he would talk about everything, including the war in Ukraine.

I'd like to see China help us out [with Russia]. I have a very good relationship... with President Xi. Very good, he said, emphasizing that Xi wants to see the war end.

Earlier this week, Trump suggested that the Chinese president can have a big influence on Putin.

Beijing has never criticized Russia's war in Ukraine, and has been accused by the US and its allies of aiding Russia's war effort, which Beijing denies. The ongoing warm relations between Russia and China were recently highlighted during a meeting involving Putin, Xi, and North Korea's Kim Jong Un, showcasing their solidarity.

As Trump made his comments on Air Force One, emergency crews in Ukraine responded to more Russian strikes, including significant incidents in Kyiv where several casualties were reported. Ukrainian President Volodymyr Zelensky reaffirmed the need for continued support from allies against such aggression.