By John Irish, Jarrett Renshaw and Andreas Rinke KANANASKIS, Alberta (Reuters) -Group of Seven leaders faced early challenges during meetings in Canada on Monday as U.S. President Donald Trump said removing Russia from the former Group of Eight over a decade ago had been a mistake.

Six of the Group of Seven leaders have discussed Russia’s war in Ukraine and international cooperation on key, non-military issues, wrapping up a summit that was forced to try and demonstrate how the wealthy nations’ club still can shape world events despite the early departure of U.

As the Group of Seven (G7) leaders gathered for a summit in Canada on Monday focusing on conflict and trade, US President Donald Trump bemoaned the exclusion of Russia. Ahead of the official start of this year's G7 summit of leading democratic economies in Canada,