Donald Trump cannot end the war in Ukraine - and it will be up to Europe to ensure Vladimir Putin is defeated, a former Republican Congressman and prominent critic of the US President has said.

And Adam Kinzinger, a former member of the US House of Representatives, believes Volodymyr Zelensky will prevail within two years if he gets the support he needs - because the Russian military is on the verge of collapse.

Speaking in an exclusive interview with investment platform , Mr Kinzinger, a vocal supporter of Ukraine, said: "The Russian military is really on its last breath. What we're seeing is they basically cannot maintain offensive combat power. The best they can do is just feed men into this meat grinder and gain almost no territory."

He highlighted the staggering losses suffered by Russian forces, suggesting that nearly a million soldiers had been killed, wounded, or gone missing since the war began in February 2022.

He continued: "If you think about that, that's twice what the US lost in World War II and they've gained almost no territory.

"So, for a defending country to win, literally all they have to do is to keep defending themselves.

"So if Donald Trump comes in and he says, 'Hey, I'm going to compel Ukraine' - for instance, this terrible deal I negotiated on the side with Russia - nobody's going to force Ukraine to do that. Ukraine is a sovereign country. They can say no."

Mr Kinzinger's remarks come as Mr Trump faces growing criticism for his approach to the war.

In recent days, he has branded Ukrainian President Volodymyr Zelensky a "dictator" while refusing to use the same term for Putin, a move that has raised eyebrows among US allies.

Meanwhile, reports have emerged of US-Russia negotiations taking place in Saudi Arabia, sparking concerns that Washington may be seeking a settlement without Ukraine's direct involvement.

The talks, led by senior US and Russian officials, have fueled speculation that Mr Trump is prioritising a deal with Moscow over Kyiv's interests.

The US President 's Defence Secretary Peter Hegseth has made it clear the Trump administration no longer regards European security as its responsibility, prompting concerns that any reduction in support could shift the balance of power in Russia's favour.

With Ukraine being left out of key discussions, critics have argued that Mr Trump's approach could undermine Kyiv's ability to defend itself.

Mr Kinzinger called on Britain - and the rest of Europe - to step up and counter any attempts by Mr Trump to weaken support for Ukraine, warning that allowing Russia to succeed would have dire consequences for European security and stability.

He said: "This is where Europe has got to recognise their strength and step up and support Ukraine and say, 'We refuse to allow Russia to win in Ukraine,'"

He stressed the broader implications of the conflict, warning that a Russian victory would trigger further instability, economic turmoil, and a deepening refugee crisis across Europe.

"Think about the refugee crisis in Europe. Think about the poverty in Ukraine if they're not given security guarantees that allow investment in that country."

Despite concerns over shifting US policy, Mr Kinzinger - one of just a handful of Republican Senators who voted to impeach Mr Trump in 2021 - remains optimistic that Ukraine has the upper hand and could decisively defeat Russia within the next year - as long as Europe and its allies remain committed to Kyiv's success.

"I think the war in Ukraine will come to an end, probably within this year, the longest maybe two years."

The former US Army officer's comments came as European nations weigh stepping up their military aid to Ukraine in response to uncertainty over US policy, with leaders considering new security guarantees to ensure Kyiv can continue resisting Russian aggression.

On Monday UK Prime Minister Sir Keir Starmer said in a speech marking the third anniversary of Russia's invasion: "For three years we have been united in opposition to Russia's barbaric invasion. And for three years we have been full of admiration for the incredible response of the Ukrainian people."

Sir Keir, who flies to Washington this week for tailks with Mr Trump on Wednesday, added: "Their voices must be must at the heart of the drive for peace."

Mr Trump and French President Emmanuel Macron met for talks at the White House on Monday.