More than 1000 migrants have left their camp near the northern Greek border, to look for a way around a border fence blocking their way into Macedonia.
On Monday a large group of migrants marched away from the sprawling tent city near Idomeni, where at least 12,000 people have been stranded in filthy conditions since Macedonia and other nations blocked their route north along the so-called Western Balkan route, a Reuters TV crew said.
Later a second group of 500 migrants set off from Idomeni to follow them.
They are looking for a gap in the barbed wire fence that Macedonia has built along its border to deter the migrants, many of whom come from war zones in Syria and Iraq.
They want to head north to wealthier European Union nations such as Germany.
Heading west from the camp, the group included many children, some walking, others pushed in strollers.
Some of the migrants made victory signs as they walked along.
There was no sign of police following the migrants.
When they reached a river, the migrants passed a rope across it and formed a "human chain" to cross, Reuters photographer Stojan Nenov said.
Migrants carried children across on their shoulders.
After crossing the river, the migrants reached the border fence and walked along it trying to find a way through into Macedonia.
Earlier, Macedonian police said three migrants -- two men and a woman -- had drowned while trying to cross a river close to the Greek border that had been swollen by heavy rain.
Greece has stepped up efforts to move thousands of migrants near the Macedonian border to sheltered camps amid fears about the spread of infectious diseases.
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.