US President Joe Biden has slammed Republican lawmakers, as he reiterates his support for Ukraine.

His Ukrainian counterpart, Volodymyr Zelenskyy, visited Washington DC to ask lawmakers to continue supporting their war efforts.

A support deal's been held up by an impasse in the US Congress on tightening immigration and border policies.

US correspondent Mitch McCann says it's unlikely the Republicans will be able to negotiate their way into a solution within a clear timeframe.

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