PODGORICA, Montenegro (AP) — Montenegro banned 87 Serbs from entering the country on Wednesday, saying they posed a security threat ahead of a European Union summit with Western Balkan leaders. The men arrived in the coastal town of Tivat on a charter flight from Serbia earlier in the day. Police said they singled out the Air Serbia plane as part of increased security checks ahead of the summit on Friday that will gather top EU and Balkan leaders. “As part of the activities aimed at preserving