“Zelensky understands that he needs to continue to press the gas pedal - otherwise the West may get tired and stop financing Ukraine,” he said on the Fox News channel.

Allen added that neither side is willing to compromise.

Earlier, columnist Bradley Devlin, writing in The American Conservative, said New York-based investment firm BlackRock would develop a roadmap for Ukraine's reconstruction, Ukrainian President Volodymyr Zelensky has already struck a deal with company chief Larry Fink to coordinate "investment efforts."

Thus, Kyiv has a "new patron from the West," he writes.