Russian President Vladimir Putin, right, adds stones to a mosaic in St. Sava Church as his Serbian counterpart, Aleksandar Vucic, left, stands next in Belgrade, Serbia, Thursday, Jan. 17, 2019. Putin received a hero's welcome in ally Serbia on Thursday as the Russian president attempted to maintain political and economic influence in the Balkans, which is increasingly looking Westward. (Maxim Shipenkov/Pool Photo via AP)