Greece is increasing efforts to move thousands of migrants near the border with Macedonia to sheltered camps, as the spread of infection became a concern with two people in a sprawling tent city diagnosed with Hepatitis A.
Stranded in filthy conditions at a muddy tent city near the northern border town of Idomeni, at least 12,000 people, among them thousands of children, were waiting to cross the frontier.
But Macedonia and other nations along the so-called Western Balkan route have closed their borders.
Scuffles broke out at the camp in recent days as destitute people scrambled for food and firewood, while many have been sleeping in the open, often in the rain amid low temperatures.
Greek authorities handed out leaflets in Idomeni on Saturday (local time) informing people that the main route to northern Europe was shut.
The pamphlets urged them to move to buildings and hospitality centres across Greece that have been set aside for the purpose, according to a government official from the country's refugee crisis management coordination body.
"Our aim is not only to relieve Idomeni from the people, our aim is that no Idomeni (camp) even exists anymore. There are structures, why should people stay in the mud?" he said.
"Greece will offer you accommodation, food and healthcare," read the leaflets which were written in Arabic, Farsi and Pashtun.
Deputy Defence Minister Dimitris Vitsas, in charge of coordinating Greek efforts to tackle the refugee crisis, said 400 people were moved from Idomeni to camps on Friday and the numbers would increase in the coming days.
EU leaders and Turkey are due to meet again on Thursday and Friday to seal a deal to try to stem illegal migrant flows from Turkey to Europe through Greece.
The squalid, overcrowded conditions of the camp in Idomeni have given rise to infections. A nine-year old Syrian girl was diagnosed with Hepatitis A on Friday, according to Greece's disease control agency.
According to the World Health Organisation, Hepatitis A is a virus which is transmitted through ingestion of contaminated food and water, or through direct contact with an infectious person. It is normally associated with lack of safe water or poor sanitation.
The agency said it had taken action to prevent the disease spreading among migrants in Idomeni.
A second individual from Idomeni was diagnosed with Hepatitis A and transferred to a hospital on Saturday, a disease control official told Reuters.
To ensure water quality, seven water transportation vehicles, three deployed by the Greek army, started operating in Idomeni.