Croatia is expecting an influx of more than 20,000 migrants over the next two weeks after Hungary sealed its border with Serbia, a minister said Thursday.

"We expect a peak within the next two weeks ... over 20,000 migrants," Health Minister Sinisa Varga said, quoted by the state-run HINA news agency.

The interior ministry said Thursday 6,200 migrants had arrived in the EU member state from Serbia in a little more than 24 hours. The refugees, eager to get to northern Europe, are now crossing into Croatia after Hungary blocked them at its frontier with Serbia.