By Tom Balmforth, Andreas Rinke, John Irish KYIV/BERLIN/PARIS (Reuters) -For Ukraine and its allies, who spent months trying to win Donald Trump over to their cause in the war started by Russia, it is back to square one.

In a reversal, President Trump appears to have backed off joining a European push for new sanctions on Russia, seemingly eager to move on to doing business deals with it.

The crucial fight being slugged out between Russia, Ukraine and their allies is for the ear of US President Donald Trump, who seems increasingly frustrated with efforts to broker peace.