A Ukrainian serviceman works on his tank, near the city of Lysychansk, Lugansk region, not far from the front line with Russia-backed separatists on April 6, 2021. - Ukrainian President Volodymyr Zelensky on April 6 urged NATO to speed up his country's membership into the alliance, saying it was the only way to end fighting with pro-Russia separatists. (Photo by STR / AFP)