By Tom Balmforth and Marko Djurica KYIV/POKROVSK, Ukraine (Reuters) -Russian missiles hit an apartment block and kindergarten in the Ukrainian capital Kyiv on Sunday, in strikes U.S. President Joe Biden condemned as “barbarism” as world leaders gathered in Europe to discuss further sanctions against Moscow. Up to four explosions shook central Kyiv in the early hours, in the first such attack on the city in weeks. “The Russians hit Kyiv again. Missiles damaged an apartment building and a kindergarten,” said Andriy Yermak, head of the president’s administration. A Reuters photographer saw a larg…