A refugee man pushes his luggage cart on the highway near the camp of Idomeni, Greece on May 25, 2016. During a police operation launched on Tuesday, thousands of refugees have been relocated from the makeshift refugee camp of Idomeni at the border between Greece and the Former Yugoslav Republic of Macedonia (FYROM) to nearby state-run reception facilities. Photo: Xinhua

A refugee child pushes his luggage cart on the highway near the camp of Idomeni, Greece on May 25, 2016. During a police operation launched on Tuesday, thousands of refugees have been relocated from the makeshift refugee camp of Idomeni at the border between Greece and the Former Yugoslav Republic of Macedonia (FYROM) to nearby state-run reception facilities. Photo: Xinhua

A refugee man pushes his luggage cart on the highway near the camp of Idomeni, Greece on May 25, 2016. During a police operation launched on Tuesday, thousands of refugees have been relocated from the makeshift refugee camp of Idomeni at the border between Greece and the Former Yugoslav Republic of Macedonia (FYROM) to nearby state-run reception facilities. Photo: Xinhua

Two refugees push their luggage carts on the highway near the camp of Idomeni, Greece on May 25, 2016. During a police operation launched on Tuesday, thousands of refugees have been relocated from the makeshift refugee camp of Idomeni at the border between Greece and the Former Yugoslav Republic of Macedonia (FYROM) to nearby state-run reception facilities. Photo: Xinhua

Refugees are pictured inside the newly established organized refugee reception center of Derveni near Greek northern city of Thessaloniki on May 25, 2016. During a police operation launched on Tuesday, thousands of refugees have been relocated from the makeshift refugee camp of Idomeni at the border between Greece and the Former Yugoslav Republic of Macedonia (FYROM) to nearby state-run reception facilities. Photo: Xinhua

Refugee children are pictured inside the newly established organized refugee reception center of Derveni near Greek northern city of Thessaloniki on May 25, 2016. During a police operation launched on Tuesday, thousands of refugees have been relocated from the makeshift refugee camp of Idomeni at the border between Greece and the Former Yugoslav Republic of Macedonia (FYROM) to nearby state-run reception facilities. Photo: Xinhua

Refugee children are pictured inside the newly established organized refugee reception center of Derveni near Greek northern city of Thessaloniki on May 25, 2016. During a police operation launched on Tuesday, thousands of refugees have been relocated from the makeshift refugee camp of Idomeni at the border between Greece and the Former Yugoslav Republic of Macedonia (FYROM) to nearby state-run reception facilities. Photo: Xinhua

Refugee children are pictured inside the newly established organized refugee reception center of Derveni near Greek northern city of Thessaloniki on May 25, 2016. During a police operation launched on Tuesday, thousands of refugees have been relocated from the makeshift refugee camp of Idomeni at the border between Greece and the Former Yugoslav Republic of Macedonia (FYROM) to nearby state-run reception facilities. Photo: Xinhua