US President Joe Biden will use his remaining months in office to strengthen Ukraine, a senior aide says, as Kyiv fights off Russia's invasion for a third year. Biden withdrew from the US elections, which are potentially perilous for Ukraine as they could see Ukraine-skeptic Donald Trump back in the White House. The prospect has raised fears in Kyiv, which relies mainly on the US for support and is preparing for Biden's handover in January. [COMPLETES VID36GA86V_EN] SOUNDBITES