Greek authorities have begun an operation to gradually evacuate the country's largest informal refugee camp of Idomeni.

It is located on the Greek-Macedonian border, where more than an estimated 8,400 people have been living for months.

The operation began at dawn Tuesday, and journalists were barred from the area. Government and police officials have said the refugees and migrants in Idomeni will be moved gradually to newly completed, organized camps.

The government's spokesman for the refugee crisis, Giorgos Kyritsis, has said police will not use force.

About 20 riot police units, comprising a total of about 400 police, were in Idomeni for the operation.