Belarusian soldiers threatened to open fire on Polish troops just across the border, the Polish Defence Ministry said on Thursday, while Belarus summoned Poland's charge d'affaires amid a row over migrants on their common frontier. Warsaw and the European Union accuse Belarus of deliberately encouraging illegal migrants to enter Poland and other EU states via Belarusian territory as a means to put pressure on the bloc over sanctions. Belarus has repeatedly denied this. Poland has declared a state of emergency in the border region. It has put up a barbed wire fence on the border and plans to build a...