More than 5,000 migrants were on their way towards the EU last night after storming lines of riot police in Macedonia.
After three days of confrontations that culminated in riot squads firing stun grenades and wielding batons at migrants trying to cross the border into Macedonia from Greece, police commanders gave up trying to hold them back.
The migrants, some with children and babies, were allowed to board buses and trains taking them towards the border with Serbia before heading north to Hungary, which is building a razor-wire fence on its frontier to prevent them from entering.
From there, they can try to head for better job prospects in countries such as Britain or Germany.
Macedonian police tried to portray the decision to let the migrants through as part of a controlled policy to avoid future bottlenecks and violent confrontations, though the move will raise fears that it will simply encourage more.
Greece and Macedonia have experienced unprecedented waves of migrants this year, with more than 160,000 arriving so far in Greece in inflat- able dinghies from the nearby Turkish coast.
Few, if any, want to remain in Greece, which is in the grip of a financial crisis, or impoverished Macedonia, which like Serbia is not yet in the EU.
The authorities in Greece, Macedonia and Serbia have no direct interest in stemming the flow of migrants, who see their countries largely as transit zones.
After deciding to let the latest swath of migrants through, Macedonia put on extra trains and buses from around the country to take them swiftly north to Serbia and the next step of a long journey from the Middle East, Africa and Asia.
"The Macedonian police told us, 'Welcome to Macedonia, trains and buses are waiting for you'," said Abdullah Bilal (41), from Aleppo in Syria.
Huge queues formed at processing centres at the weekend as migrants waited for papers to legalise their transit north through Serbia before they try to cross by foot into Hungary and Europe's borderless Schengen zone.
Bratislav Gasic, Serbia's defence minister, visiting a migrant reception centre near the southern border with Macedonia, said more than 5,000 people had entered overnight as Macedonia cleared the backlog.
"We expect the wave in the next day or two to be of a similar intensity," he said. "Papers are being issued around the clock."