The United States' approach to the Russia-Ukraine conflict has dramatically changed with the new administration in Washington.

US President Donald Trump, who started his second term last month, has questioned the multibillion-dollar aid and weapons sent to Ukraine during the Joe Biden administration.

Trump has called for a return of aid money from Kyiv, and demanded that Ukraine provide the US with rare earth minerals in exchange.

A deal for the minerals is estimated to be worth $500 billion, a price tag Ukraine has balked at and which is much higher than published US aid figures. Despite growing pressure from the US side, Ukrainian President Volodymyr Zelensky is "not ready" to sign a minerals deal with the US, Agence France-Presse reported, citing a source. But Trump said on Saturday the US is "close" to an agreement on sharing revenue from Ukrainian minerals.

Zelensky and European Union representatives were not invited for preliminary talks between the US and Russia on Feb 18.

The talks to settle the three-year conflict between Russia and Ukraine — which started on Feb 24, 2022 — were led by US Secretary of State Marco Rubio and Russian Foreign Minister Sergey Lavrov as they met in Saudi Arabia's capital Riyadh on Tuesday.

The discussions were a prelude to an expected meeting between Trump and Russian President Vladimir Putin later this month.

Jack Midgley, principal of the global consultancy Midgley & Co, told China Daily that the conflict's outcome rests with Russia and the US.

"If the United States and Russia reach an agreement, the Ukrainians have to come along," Midgley said.

"If you look at the actual assistance that's gone into the war, the Americans have put in about $114 billion. The next biggest contributions are from Germany and the UK, and those are at about 10 percent of what the Americans have put in," he said.

The figures on the number of casualties in the conflict vary widely. According to figures released by Kyiv, United Nations statistics, and open-source data published by BBC Russia, the death toll of Ukrainian and Russian soldiers, and Ukrainian civilians stood at 148,359 as of Feb 13.

On Feb 16, Zelensky said more than 46,000 Ukrainian soldiers had been killed, and in a Feb 4 interview with journalist Piers Morgan, he said 390,000 Ukrainian soldiers were injured.

Midgley said: "There are some areas where the Americans and the Russians agree or have a common interest."

The first one is excluding Ukraine from NATO, he said. "The Americans don't want Ukrainians in NATO as it would mean providing a nuclear guarantee to Ukraine, which is not in America's interest. And the Russians don't want Ukraine in NATO either, as it means there will be American, British and German troops stationed in Ukraine."

He said the second sticking point is EU membership for Ukraine. "If you put Ukraine in the EU, it is the poorest country in Europe. They will require huge economic assistance."

"There's a third area … safety of the Chernobyl nuclear plant (in northern Ukraine). The Chernobyl plant … is an environmental disaster. And it needs huge investment to keep it safe," he said.