Europe migrant crisis: Serbia, Macedonia limit entry of asylum seekers by

She says Serbia has overnight turned back to Macedonia a few 200 migrants, and Macedonia has not let them in.

Croatia's Ostojic is warning that countries must coordinate actions to avoid problems with the possible backlog of migrants stuck along the Balkan route, AP reports.

Serbia and Macedonia have started to limit the passage of "refugees who are not coming from war-affected areas of Syria, Iraq, and Afghanistan".

Aleksandra Kraus, a UNHCR spokeswoman in Macedonia, said Thursday that Macedonian authorities had begun allowing only people from warzones to enter the country because Serbian authorities had imposed the same criteria on those attempting to cross the Macedonian-Serbian border. "We are not the final destination country, they just pass through Serbia and it will remain so", Vulin said.

"We have formally announced to Croatia that we will return a group of economic migrants".

Jasmin Redzepi, president of Macedonian NGO LEGIS whose activists have been helping refugees and migrants at the border with Greece, said that Macedonia was also allowing only Iraqis, Afghans and Syrians into the country.

Serbia and Macedonia have begun restricting the entry of refugees to those from certain countries, leaving hundreds of people stranded on borders.

The partial closure of the borders could trigger huge pileups of desperate people along the Balkan corridor that has seen hundreds of thousands of people cross as they head to wealthy European Union states, mostly Germany. Many are fleeing violence in the Middle East, but others are also economic migrants from Asian and African countries trying to reach western European nations.

Migrants arrived by bus at a petrol station near the Serbian border town of Sid, where police checked their papers.

Meanwhile, nearby Croatia has refused a request from Slovenia to take back migrants who had crossed the countries' shared border, a police spokesman said.