[Police operation to evacuate a makeshift camp for refugees and migrants near the village of Idomeni]By Phoebe Fronista and Fedja Grulovic IDOMENI, Greece (Reuters) - Greek police on Tuesday started moving some of the 8,000 migrants and refugees stranded in a makeshift camp on the sealed northern border with Macedonia to state-run facilities further south. At one point more than 12,000 lived there after several Balkan countries shut their borders in February, barring migrants and refugees from central and northern Europe. Greek authorities said they planned to move individuals gradually to state-supervised facilities further south which currently have capacity of about 5,000 people.