By Alexandros Avramidis IDOMENI, Greece (Reuters) - Greek police on Wednesday loaded hundreds of migrants who have been stranded for three weeks at the Macedonian border onto buses bound for Athens, a police official and a Reuters witness said, ending their hopes of reaching northern Europe. Scuffles broke out but not on the scale of recent clashes between police and the roughly 1,200 people - mostly men from Pakistan, Morocco and Iran - stuck near the town of Idomeni, after Macedonia began filtering migrants by nationality. Some 30 men resisted police and were taken to a police station but were later put on the Athens-bound buses as well.