By Stephanie Nebehay GENEVA (Reuters) - Up to 3,000 migrants are expected to cross into Macedonia every day in the coming months, most of them refugees fleeing war, particularly from Syria, the United Nations said on Tuesday. Member states of the European Union must share the burden by establishing "equitable re-distribution" of desperate families seeking asylum in the bloc, the U.N. refugee agency said. Nearly 300,000 people have crossed the Mediterranean this year, including nearly 181,500 in Greece and 108,500 in Italy, according to the U.N. High Commissioner for Refugees (UNHCR).