Migrants walk as they cross the border from Hungary to Austria in Nickelsdorf, September 11, 2015. (Reuters)

Migrants walk along a railway track as they cross the Hungarian border with Serbia near a collection point in Roszke, Hungary, September 11, 2015. (Reuters)

Migrants walk along a railway track as they cross the Hungarian border with Serbia near a collection point in Roszke, Hungary, September 11, 2015. (Reuters)

A migrant carries a baby as she crosses the Hungarian border with Serbia near a collection point in Roszke, Hungary, September 11, 2015. (Reuters)

Migrants walk as they cross the border from Hungary to Austria in Nickelsdorf, Austria September 11, 2015. (Reuters)

Migrants pass behind a barbwire fence near a collection point in Roszke, Hungary, September 11, 2015 (Reuters)

A migrant flashes a victory sign as he arrives in Hungary from Serbia in Roszke, September 11, 2015. (Reuters)

Syrian refugee child Zaid Hussein, 4, is held by his mother while sitting inside their tent at a makeshift camp for asylum seekers in Roszke, southern Hungary, Friday, Sept. 11, 2015 (AP)

Migrants walk as they cross the border from Hungary to Austria in Nickelsdorf, September 11, 2015. (Reuters)

Migrants walk wrapped in emergency blankets as they cross the border from Hungary to Austria in Nickelsdorf, September 11, 2015. (Reuters)

Hungarian police officers secure the bus that will take migrants to the center for asylum seekers near Roszke, southern Hungary, Friday, Sept. 11, 2015 (AP)

Migrants pull the wheelchair of disabled man in front of a makeshift camp for asylum seekers near Roszke, southern Hungary, Friday, Sept. 11, 2015 (AP)

A child pulls another child in a plastic crate as they cross the border from Hungary to Austria in Nickelsdorf, Austria September 11, 2015 (Reuters)

A migrant gestures the peace sign after crossing the border from Hungary to Austria in Nickelsdorf, September 11, 2015 (Reuters)

A migrant sits wrapped in an emergency blanket at the crossing point between Hungary and Austria in Nickelsdorf, September 11, 2015 (Reuters)

Migrants walk along a railway track as they arrive in Hungary from Serbia in Roszke, September 11, 2015. (Reuters)

Migrants pass behind a barbwire fence near a collection point in Roszke, Hungary, September 11, 2015. (Reuters)

Migrants gesture the peace sign after they cross the border from Hungary to Austria in Nickelsdorf, September 11, 2015. (Reuters)

A girl pulls a suitcase as she walks to cross the border from Hungary to Austria in Nickelsdorf, Austria September 11, 2015. (Reuters)

A migrant carries a baby near a collection point in Roszke, Hungary, September 11, 2015. (Reuters)

Migrants receive clothes near a collection point in Roszke, Hungary, September 11, 2015. (Reuters)

A migrant gestures a peace sign after crossing the border from Hungary to Austria in Nickelsdorf, September 11, 2015 (Reuters)