Hundreds of refugees have broken through a police cordon and fled from a train being held near an asylum camp in Hungary.
Surprised riot police scrambled for their helmets as the huge crowd suddenly surged from the front of the train at Bicske station, near Budapest, and ran down a track leading towards Austria, 84 miles to the west.
Officers were able to block only a minority of the estimated 500 people on the train, and pushed them back on board amid much shouting and screaming and children crying.
The break-out came hours after hundreds of other refugees who had been stuck for days in Budapest gathered their belongings and started marching out of the capital, vowing to make it to Austria on foot.
They set out from Keleti railway station after Hungarian authorities blocked them from boarding western-bound trains.
They carried their belongings in bags and backpacks as they snaked through the capital in a line stretching nearly half a mile, hampering traffic at times, as they began the 100-mile journey to the Austrian border.
The refugees, many fleeing war in Syria, want to reach Germany or elsewhere in the West and are trying to avoid registering in Hungary, which is economically depressed and more likely to return them to their home countries than many western European nations.
Under European law, asylum seekers are approved or disapproved in the countries where they first register.
One man, 23-year-old Osama Morzar, from Aleppo, Syria, was so determined not to be registered in Hungary that he removed his fingerprints with acid, holding up smooth finger pads as proof.
"The government of Hungary is very bad," said Mr Morzar, who studied pharmacology at Aleppo's university. "The United Nations should help."
A couple from Baghdad, Mohammed and Zahara, who marched with a toddler, said they had been in a Hungarian asylum camp and were roughed up by guards because they refused to be fingerprinted.
She said she has family in Belgium and is determined to seek asylum there. They would not give their last names.
The break-out at Bicske came after a two-day stand-off with police close to one the country's five camps for asylum seekers.
Hundreds of people had sat on the train, some with tickets they had purchased to Berlin or Vienna. Although some eventually relented and registered at the asylum centre, most were determined not to.
"The situation is so bad. We have so many sick people on the train. We have pregnant women, no food, no water," said Adnan Shanan, a 35-year-old from Latakia, Syria, who said he was fleeing war in his homeland.
"We don't need to stay here one more day. We need to move to Munich, to anywhere else, we can't stay here. We can't wait until tomorrow. We need a decision today, now," Mr Shanan said.
The events came a day after a round of recriminations among EU leaders. Prime minister Viktor Orban has said the human wave is a German problem, but chancellor Angela Merkel said the obligation to protect refugees "applies not just in Germany, but in every European member".
Mr Orban reiterated on Hungarian state radio his determination to stop the refugees.
"Today we are talking about tens of thousands but next year we will be talking about millions and this has no end.
"We have to make it clear that we can't allow everyone in, because if we allow everyone in, Europe is finished. If you are rich and attractive to others, you also have to be strong because if not, they will take away what you have worked for and you will be poor too."