REPUBLIKA.CO.ID, IDOMENI -- Greek police started moving migrants and refugees out of a sprawling tent camp on the sealed northern border with Macedonia on Tuesday where thousands have been stranded for months trying to get into western Europe.

Reuters witnesses saw several bus loads of migrants leaving the makeshift camp of Idomeni early on Tuesday morning, with about another dozen buses lined up. It appeared to be mainly families who were on the move.

Greek authorities said they planned to move individuals gradually to state-supervised facilities further south in an operation expected to last several days.

"The evacuation is progressing without any problem," said Giorgos Kyritsis, a government spokesman for the migrant crisis.