Migrants cradling young children have blocked a motorway in central Greece demanding onward passage to Macedonia, part of a growing bottleneck of refugees stranded by new border restrictions and closures across Europe.
Families chanted "We want to go" after police stopped their convoy at Tempe on Wednesday and authorities stepped up measures to control the flow of people passing through the country on their way to more prosperous nations further north.
Reuters journalists saw hundreds of others gathered at petrol stations and motels along the 530-km route from Athens to Macedonia, where guards periodically opened the border on Wednesday morning, letting 100 people through at a time.
Greece has protested against restrictions imposed by countries further north along the main land migration route into Europe.
Migrant Minister Yannis Mouzalas singled out controls brought in by Austria, Slovenia, Croatia, Serbia and Macedonia after a meeting of their police chiefs last week.
"It's scandalous... that five police chiefs can overturn a decision of European Union prime ministers on the matter," Mouzalas told Reuters in Athens.
Austrian Foreign Minister Sebastian Kurz brushed off criticism of his country's plans to impose daily caps on migrants, saying on Wednesday that Greece needed to do more to reduce the flow.
More than a million migrants and refugees passed through Greece last year, many of them fleeing conflicts in Syria and Afghanistan.
Another 1600 arrived on the mainland from outlying islands bordering Turkey on Wednesday morning.
Two Greek government officials said there were an estimated 20,000 migrants stranded in the country.
"When there is a bottleneck, the bottle could break, and where we had a controlled movement of individuals ... a broken bottle could result in an uncontrolled, illegal influx," Mouzalas said.
Balkan decisions to halt the flow would escalate, and not reduce, illegal migration, he added.
