Hundreds of migrants have broken through police lines near Hungary's southern border with Serbia and have begun marching north towards Budapest.
The move came as Britain and France pledged to take in tens of thousands more refugees to try to ease the crisis.
As European leaders debate how to share responsibility for more than 340,000 people from the Middle East, Africa and Asia who are seeking refuge, Germany promised to spend billions of euros in extra aid for those already there and those yet to arrive.
France pondered whether increased airstrikes against Islamic State militants would help to stem the flow of those fleeing Syria.
But the Hungarian prime minister scoffed at a proposed quota system for refugees in the 28-member European Union, saying it would not work unless Europe first secured its borders.
Hungary’s inability to control the flow of people across its southern border with Serbia was apparent on Monday, as crowds tired of waiting for buses at Hungary’s first migrant holding centre near the border village of Roszke tore down flimsy police tape, advanced down a country road and walked straight through rows of police trying to block them.
Officers shoved individual migrants and fired jets of pepper spray, but it had little effect as about half of the 500-strong crowd reached the M5 motorway that connects Serbia and Hungary.
They headed north along the shoulder, raising their arms and chanting “Germany! Germany!”
Police merely walked beside them as a lone helicopter monitored the marchers’ progress north as darkness fell. The motorway was blocked for nearly 30 miles as a precaution.
A few hours later, as the marchers paused by the roadside to try to sleep in the cold on the pavement, police delivered buses and requested they board for delivery to a refugee camp. Most refused.
The northward march mirrored Friday's surge of people down Budapest's motorway toward Austria, which forced Hungary to concede defeat and bus thousands to the Austrian border.
Germany’s rail company said it had carried 22,000 asylum seekers over the weekend on more than 100 trains, a number boosted by the fact that Hungary again has dropped visa checks on foreigners buying train tickets for the wealthier countries to the west, particularly Germany.
Following an overnight Cabinet meeting, Germany said it would set aside €6 billion to boost aid for asylum seekers and hire 3,000 more federal police. It also planned to make it easier to build refugee housing and for non-German speakers to hold jobs.
German chancellor Angela Merkel reflected on what she called "a moving, in some parts breathtaking weekend behind us," when Austria and Germany threw open their borders for thousands of asylum-seekers trying to get out of Hungary. She said all EU countries could help accommodate the families fleeing war and poverty.
French president Francois Hollande said his country would take in 24,000 refugees over the next two years. To relieve the burden on Germany, he told Merkel that France would take in 1,000 of the migrants who have just arrived from Hungary. Most say they are fleeing the civil war in Syria.
Saying France has to target “the causes of these horrors,” Mr Hollande announced possible airstrikes against IS targets in Syria, an idea he had previously resisted. France will send reconnaissance flights over Syria starting today, he said, and “we will be ready to strike”.
Calm returned Monday to the main Austrian-Hungarian border point, where thousands crossed over the weekend by foot, bus, train and car after complaining of neglect and human rights violations in Hungary and refusing to stay in refugee camps there.
Austrian chancellor Werner Faymann and other EU leaders said Hungarian prime minister Viktor Orban bungled Hungary's intake of migrants so badly that it left Austria and Germany no choice but to open their borders on Saturday.
Mr Orban compared Hungary to a “black sheep” representing a voice of reason in the European flock of countries.
He argued that the EU first must focus on security measures to force those from troubled lands to seek asylum in neighbouring countries, not in the heart of Europe. He said the current discussions on a new quota to handle 120,000 migrants soon would lead to discussions on hosting millions more.
PA