Croatian Interior Minister Ostojic tells refugees
Croatia has closed seven of its eight road border crossings with Serbia following a huge influx of migrants.
Officials in Zagreb said they had no choice after more than 10,000 people entered the country a day after Hungary fenced off its border with Serbia.
Meanwhile, Slovenia said it had stopped a group of migrants on a train and would return them to Croatia.
Huge numbers of people heading north from the Mediterranean have created a political crisis in the European Union.
Croatian officials said roads leading to the border crossings had also been shut.
The crossing on the main road linking Belgrade and Zagreb – at Bajakovo – appeared to be the only one left open.
The BBC’s Guy Delauney in Zagreb says the closures have cut off the migrants’ main land route from Greece to northern Europe.
Croatia has tried to take people to asylum centres but the overwhelming numbers mean that many people have been left on the streets, he says.
Some have told the BBC they plan to walk north to neighboring Slovenia which is in the EU’s border-free Schengen Area.
On Thursday, Croatian Interior Minister Ranko Ostojic said his country was “absolutely full”.
He said his message to the migrants was: “Don’t come here anymore. Stay in refugee centres in Serbia and Macedonia and Greece. This is not the road to Europe. Buses can’t take you there. It’s a lie.”
Croatian Prime Minister Zoran Milanovic said the country had “limited capacity”.
Scuffles broke out in two locations on the border with Serbia on Thursday after people were left waiting for hours for transport further north.
Crowds briefly broke through police lines at Tovarnik and Batina – two of the crossings now closed.
The BBC’s Lyse Doucet, at Tovarnik, said buses arrived just before midnight but werent enough to transport everyone. Drivers said people were being taken to a reception centre. Thousands of people left behind are spending the night sleeping on roadsides and in fields.
There was a mad rush as the first train for 24 hours pulled in on Thursday evening, she adds.