Thousands of migrants are searching for ways to cross Greece's land border days after Turkey declared its frontiers with Europe open.
Many of those hoping to enter Greece were wading or rowing across the Evros River that runs along most of the length of the Turkish border.
Turkey declared its borders with Europe open in an attempt to force the EU into helping it handle the growing fallout from Syria's civil war.
Greek authorities said they thwarted an attempt by approximately 1,000 people overnight to make their way across the Evros wetland area at the southern end of the border.
They said that in the 24 hours between Monday and Tuesday morning, they had prevented a total of 5,183 people from entering Greece, and arrested 45 people, mostly from Afghanistan, Pakistan, Morocco and Bangladesh.
Greece has made clear its borders are shut. It has sent military and police reinforcements to the area, which have used tear gas and water cannons to repel mass attempts by migrants to cross into the country. Authorities have also set up cordons of police and army checks on and near the border, arresting those who managed to make it through.
On Tuesday morning, two men – one from Mali and one from Afghanistan – were seen being arrested by Greek authorities shortly after crossing the border and being loaded into a van with about 20 more people from Somalia, Afghanistan, Bangladesh and Iraq.
Turkey announced last week it was easing restrictions on those wishing to cross into Europe, leading to a wave of migrants to mass along its western frontier. The vast majority appeared to be Afghans, along with people from a wide variety of countries including Iran, Iraq, Bangladesh and Syria.
Turkey's announcement upended its previous policy of containing refugees and other migrants under an agreement with the EU.
Turkish President Recep Tayyip Erdogan, whose country hosts more than 3.5 million Syrian refugees, has demanded more support from Europe. He says his country is facing an imminent and dramatic new influx of refugees from the war in Syria where growing clashes between Turkish and Syrian troops has raised alarm.
Migrants have also been trying to reach Greece by making the short but often perilous sea crossing to islands from the nearby Turkish coast. A young boy died on Monday after the dinghy he was in capsized off the coast of the island of Lesbos. The other 47 people in the boat were rescued.
On Monday night, Greek authorities said they had stopped more than 24,000 attempted illegal crossings at the land border with Turkey since early on Saturday, and arrested 183 people - very few of whom were Syrians.
