Ukrainian President Volodymyr Zelenskyy hailed the "extraordinary" Gaza ceasefire as bringing hope that US President Donald Trump could broker an end to the Russian invasion of his country.

"When peace is achieved for one part of the world, it brings more hope for peace in other regions," Zelenskyy said on Monday on social media.

He added: "If a ceasefire and peace have been achieved for the Middle East, the leadership and determination of global actors can certainly work for us too, in Ukraine."

Trump had once vowed he could end the war in a matter of hours, but despite several rounds of talks and a summit with Russian President Vladimir Putin, there has been no significant progress towards a peace deal.

The US leader has grown increasingly frustrated with Putin in recent weeks and recently said he could see Ukraine reclaiming every territory seized by Russia.

Moscow's army currently controls around a fifth of Ukraine, including the Crimean peninsula which it captured and annexed in 2014.

German Chancellor Friedrich Merz also urged Trump to carry the momentum from brokering the Israel-Hamas ceasefire into efforts on Ukraine.

"We also hope that the American president will now use the influence he has exerted on the parties involved in the (Middle East) to work with us on the Russian government," Merz said in Egypt, where he was to attend a summit of world leaders, including Trump.

Merz added that he will discuss the Russia-Ukraine war settlement with Trump at the summit.