Callas outraged by Trump's decision to invite Putin to the G20 summit The head of European diplomacy, Kaya Callas, believes that the idea of inviting Putin to the G20 summit in December "raises a number of questions." In her opinion, the participation of the Russian president in the G20 leaders' summit risks legitimizing Russia's return to international forums. The G20 summit is scheduled for December 14-15 at the Trump-owned golf club in Doral, Florida.