A group of Syrian refugees gather around an open fire as a storm is approaching at a field at the Greek-Macedonian border, near the village of Idomeni, August 21, 2015. Macedonian police fired tear gas and stun grenades to drive migrants and refugees back from its southern border from Greece on Friday but crowds continued to build up at a new bottleneck in an increasingly desperate flight to western Europe. At least 10 people were hurt in the brief flare-up, a day after the impoverished Balkan country declared a state of emergency on its border to halt a daily influx of up to 2,000 Syrians, Afghans, Iraqis and others heading north. (Photo by Yannis Behrakis/Reuters)

Refugees camp on a field as lightning strikes during a storm at the Greek-Macedonian border, near the village of Idomeni, August 21, 2015. (Photo by Yannis Behrakis/Reuters)

Refugees camp on a field at the Greek-Macedonian border, near the village of Idomeni, August 21, 2015. (Photo by Yannis Behrakis/Reuters)

Syrian refugees sit in front of Macedonian riot police guarding the Greek-Macedonian border line, near the village of Idomeni, August 21, 2015. (Photo by Yannis Behrakis/Reuters)

Syrian refugees sit in front of barbed-wire at the Greek-Macedonian border, near the village of Idomeni, August 21, 2015. (Photo by Yannis Behrakis/Reuters)

Syrian refugees sit in front of a barbed-wire at the Greek-Macedonian border, near the village of Idomeni, August 21, 2015. (Photo by Yannis Behrakis/Reuters)

Syrian refugee children scream as they are siting in front of Macedonian riot police at the Greek-Macedonian border, near the village of Idomeni, August 21, 2015. (Photo by Yannis Behrakis/Reuters)

A Syrian refugee woman cries by her husband as she pushed away by Macedonian riot police (L) at the Greek-Macedonian border, near the village of Idomeni, August 21, 2015. (Photo by Yannis Behrakis/Reuters)

A Syrian refugee is carried by medics after collapsing at the Greek-Macedonian border, near the village of Idomeni, August 21, 2015. (Photo by Yannis Behrakis/Reuters)

A Syrian refugee woman cries on her husbands arms as they wait to cross into Macedonia at the Greek-Macedonian border, near the village of Idomeni, August 21, 2015. (Photo by Yannis Behrakis/Reuters)

A Macedonian riot policeman stands guard as a Syrian refugee woman sits behind barbed-wire at the Greek-Macedonian border, near the village of Idomeni, August 21, 2015. (Photo by Yannis Behrakis/Reuters)

An Afghani refugee has his prosthetic leg removed as he sits behind barbed wire at the Greek-Macedonian border, near the village of Idomeni, August 21, 2015. (Photo by Yannis Behrakis/Reuters)

Syrian refugees sit behind barbed wire as they wait to cross into Macedonia at the Greek-Macedonian border, near the village of Idomeni, August 21, 2015. (Photo by Yannis Behrakis/Reuters)

A Syrian refugee child stands in front of Macedonian riot police at the Greek-Macedonian border, near the village of Idomeni, August 21, 2015. (Photo by Yannis Behrakis/Reuters)

An aerial view taken from a drone of migrants queueing to pass the Greek-FYROM border to Gevgelija, The Former Yugoslav Republic of Macedonia, from the border village of Idomeni, northern Greece, 21 August 2015. Macedonian police clashed with thousands of migrants attempting to break into the country after being stranded in no-man's land overnight, marking an escalation of the European refugee crisis for the Balkan country. Macedonia had closed the border to refugees and declared a crisis situation in the border zone, calling upon the military to curb the inflow of migrants and deploy border patrols. (Photo by Nikos Arvanitidis/EPA)

Migrants wait to enter Macedonia from Greece on the border line with Greece, near the southern Macedonia's town of Gevgelija, Friday, August 21, 2015. About 39,000 people, mostly Syrian migrants, have been registered as passing through Macedonia in the past month, twice as many as the month before. (Photo by Boris Grdanoski/AP Photo)

UNHCR workers help migrants who have collapsed while the crowd of migrants were pushing the police to enter into Macedonia, at the railway tracks on border line with Greece, near the southern Macedonia's town of Gevgelija, on Friday, August 21, 2015. (Photo by Boris Grdanoski/AP Photo)

Three boys migrants wait for the rest of their family to enter into Macedonia from Greece, on the border line with Greece, near the southern Macedonia's town of Gevgelija, on Friday, August 21, 2015. (Photo by Boris Grdanoski/AP Photo)

Migrants confront Macedonian police during clashes at the Greek-Macedonian border, August 21, 2015. Macedonian police drove back crowds of migrants and refugees trying to enter from Greece on Friday after a night spent stranded in no-man's land by an emergency decree effectively sealing the Macedonian frontier. A Reuters reporter said tear gas was fired and saw at least four bloodied migrants taken for treatment on the Greek side of the border. (Photo by Alexandros Avramidis/Reuters)

Migrants carry their injured fellow during clashes with Macedonian police at the Greek-Macedonian border, August 21, 2015. (Photo by Alexandros Avramidis/Reuters)

A migrant reacts as he carries a child during clashes with Macedonian police at the Greek-Macedonian border, August 21, 2015. (Photo by Alexandros Avramidis/Reuters)

Macedonian police vehicles are seen behind migrants at the Greek-Macedonian border, August 21, 2015. (Photo by Alexandros Avramidis/Reuters)

Macedonian police stand guard in front of migrants at the Greek-Macedonian border, August 21, 2015. (Photo by Alexandros Avramidis/Reuters)

Macedonian police stand guard in front of migrants at the Greek-Macedonian border, August 21, 2015. (Photo by Alexandros Avramidis/Reuters)

Migrants gather as they are stopped by Macedonian police at the Greek-Macedonian border, August 21, 2015. (Photo by Alexandros Avramidis/Reuters)

Macedonian policemen stand guard in front of migrants at the Greek-Macedonian border, August 21, 2015. (Photo by Alexandros Avramidis/Reuters)

A migrant reacts after he was injured during clashes with Macedonian police at the Greek-Macedonian border, August 21, 2015. (Photo by Alexandros Avramidis/Reuters)

A migrant reacts as he carries a child during clashes with Macedonian police at the Greek-Macedonian border, August 21, 2015. (Photo by Alexandros Avramidis/Reuters)

Migrants carry their injured fellow during clashes with Macedonian police at the Greek-Macedonian border, August 21, 2015. (Photo by Alexandros Avramidis/Reuters)

Migrants rest on a railway track at the Greek-Macedonian border, August 21, 2015. (Photo by Alexandros Avramidis/Reuters)

A migrant rests as a Macedonian policeman stands guard at the Greek-Macedonian border, August 21, 2015. (Photo by Alexandros Avramidis/Reuters)

Migrants clash with Macedonian police at the Greek-Macedonian border, August 21, 2015. (Photo by Alexandros Avramidis/Reuters)

Macedonian special policemen guard the border as more than a thousand immigrants wait at the border line of Macedonia and Greece to enter Macedonia near the Gevgelija railway station August 21, 2015. Macedonian police drove back crowds of migrants and refugees trying to enter from Greece on Friday after a night spent stranded in no-man's land by an emergency decree effectively sealing the Macedonian frontier. (Photo by Ognen Teofilovski/Reuters)

Macedonian special policemen guard the border as more than a thousand immigrants wait at the border line of Macedonia and Greece to enter Macedonia near the Gevgelija railway station August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

Macedonian special policemen guard the border as more than a thousand immigrants wait at the border line of Macedonia and Greece to enter Macedonia near the Gevgelija railway station August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

Macedonian special policemen guard the border as more than a thousand immigrants wait at the border line of Macedonia and Greece to enter Macedonia near the Gevgelija railway station August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

Macedonian special policemen guard the border as more than a thousand immigrants wait at the border line of Macedonia and Greece to enter Macedonia near the Gevgelija railway station August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

A group of immigrants who has made through police blockades arrive at the Gevgelija railway station August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

A group of immigrants who have made through police blockades arrive at the Gevgelija railway station August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

A group of immigrants who have made through police blockades rest at the Gevgelija railway station August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

A woman collapses at the border line dividing Macedonia and Greece August 21, 2015. At least 1,000 migrants and refugees pressed against Macedonian police lines on the Greek-Macedonian border on Friday and at least 10 people appeared to faint in the crush. People could be heard screaming and medical workers raced to treat those who passed out or were hurt. The crush ensued after police let several hundred through into Macedonia, having kept them out since Thursday under an emergency decree. (Photo by Ognen Teofilovski/Reuters)

A woman reacts to the police at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

A woman reacts to the police at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

A woman gestures to the police at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

A baby cries at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

A man reacts at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

Girls cry as they get separated from their family at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

Members of the media carry a man who collapsed at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

A man kneels next to his collapsed wife at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

People react as they are held back by police at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

A woman reacts to the police at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

People carry their friend who collapsed at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

A boy gestures to the police at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

People react as they are held back by police at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

U.N. workers help a woman who collapsed at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

A woman is seen at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

U.N. workers help a woman who collapsed at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

A woman is seen at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

U.N. workers help a woman at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

U.N. workers help a woman who collapsed at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

U.N. workers help a man who collapsed at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

Men help their friend who collapsed at the border line dividing Macedonia and Greece August 21, 2015. (Photo by Ognen Teofilovski/Reuters)

A man assists a fallen woman as police block a group of migrants trying to cross the Macedonian-Greek border near the town of Gevgelija on August 21, 2015. Macedonia said on August 20 that it had declared a “state of emergency” on its southern border with Greece and would draft in the army to help control the influx of migrants crossing the frontier. (Photo by Robert Atanasovski/AFP Photo)