ATHENS (Reuters) - Greek Prime Minister Alexis Tsipras said on Friday all European Union member states should agree to a compulsory burden sharing over the migrants crisis. Tsipras said the population of migrants and refugees in the country had been accumulating since neighbouring states progressively restricted border passage through the Balkans. "We will demand that all member states share the responsibility of a crisis which is beyond us," Tsipras told journalists. "We cannot continue together if our only concern is that each get on with it themselves." (Reporting By Renee Maltezou)