The United States has "paused" intelligence sharing with Ukraine after a dramatic breakdown in relations between Kyiv and the White House, CIA director John Ratcliffe said on Wednesday.

President Donald Trump and Ukraine's leader Volodymyr Zelensky had a public falling-out in the Oval Office last week, followed by Ukraine's top ally suspending crucial US military aid.

Ratcliffe confirmed that intelligence sharing had also been frozen as Ukraine seeks to beat back the Russian assault.

"President Trump had a real question about whether President Zelensky was committed to the peace process," Ratcliffe told Fox News.

Ratcliffe said the pause "on the military front and the intelligence front" was temporary, and the United States will again "work shoulder to shoulder with Ukraine."

Trump said on Tuesday that Zelensky told him Kyiv was ready for talks with Moscow and the finalisation of a US minerals deal, as Ukraine works to move on after the Oval Office spat.

Zelensky has sought to bring Trump back onside, posting on social media that their clash was "regrettable" and he wanted "to make things right."

In his address to the US Congress later on Tuesday, Trump read aloud from a letter from Zelensky.

"The letter reads, 'Ukraine is ready to come to the negotiating table as soon as possible to bring lasting peace closer. Nobody wants peace more than the Ukrainians,'" Trump told US lawmakers. (AFP)