IDOMENI (AFP) - At least 200 police started clearing Greece's squalid Idomeni camp Tuesday (May 24) on the border with Macedonia, where over 8,400 migrants are living, according to AFP.

A helicopter hovered over the camp, where some 20 police vans and dozens of plainclothes police officers were on site as the operation got under way after a harsh winter prompted many to try to force their way across the border.

No force was used as officers, who started to arrive at the camp Monday, urged migrants to leave their tents and board buses to take them to shelters.

Officials have said 6,000 spots are available at reception centres, and that most of the migrants are to be moved to camps at former industrial facilities near Greece's second city Thessaloniki over 10 days.

The migrants have spent a brutal winter in the freezing rain and mud, with aid groups struggling to keep them fed and healthy.

Many of the camp's residents are women and children keen to be reunited with male relatives who have pushed ahead on their own - with the aid of smugglers - hoping to find a place of refuge in EU states more financially viable than debt-hit Greece.

The leftist government of Greek Prime Minister Alexis Tsipras has for months been trying to persuade many of the migrants to move away from makeshift tent cities at Idomeni and the port of Piraeus for their own comfort and safety.

Through persuasion, the number of migrants at Piraeus was brought down from around 5,000 people in March to 1,500. But many are wary of relocating to organised camps away from the border or the city of Athens, because it could be harder to find people-smuggling contacts.