Tensions between Zelensky and Trump over the US President's outreach to Moscow have exploded this week in a series of escalating barbs traded in press conferences and on social media. Amid the war of words, Zelensky said Thursday he had held a "productive meeting" with US envoy Keith Kellogg. In the US, some of Trump's team doubled down on their attacks on Zelensky, and VP Vance on Thursday defended Trump's negotiations with his Russian counterpart Vladimir Putin.