German Chancellor Angela Merkel says "Europe as a whole needs to move" on how to deal with refugees and migrants arriving in the EU.
"If Europe fails on the question of refugees, then it won't be the Europe we wished for," she said.
She was speaking after Austrian authorities arrested five suspected people smugglers along the country's eastern borders.
On Thursday, 71 dead migrants were found near the Hungarian border.
Austrian police say more than 200 others were found alive overnight.
Ms Merkel said European countries must share the burden of refugees.
Germany is the main destination for migrants arriving on the EU's eastern borders and expects the number of asylum seekers it receives to quadruple to about 800,000 in 2015.
Mrs Merkel said "Germany is a strong country - we will manage."
But she said there would be "no tolerance for those who question the dignity of other people" after a spate of arson attacks on refugee shelters and anti-migrant demonstrations.
"The number of people... helping strangers get through cities and communities and even taking them into their homes is far greater than the number of xenophobes," she went on.
Mrs Merkel's call for greater co-operation was echoed by French Prime Minister Manuel Valls, who warned that Europe's migrant crisis would be a "long and difficult challenge".
Also on Monday, trains from Budapest carrying hundreds of migrants were stopped at the Austrian frontier. Austria's rail service OeBB said the route from Budapest was facing severe disruption due to "overcrowding".
Austrian police said they would turn back anyone on board who had made a request for asylum in Hungary - but it is not clear if this actually happened.
Once in Austria, migrants would have two weeks to decide whether or not they wanted to claim refugee status there, police said.
Trains were later allowed to proceed and hundreds of migrants arrived in Vienna on Monday evening. Many of them immediately boarded trains bound for Germany.
Austria also introduced extra checks on vehicles entering from Hungary on Sunday evening, causing long traffic jams on Hungary's major roads leading to the Austrian border.
The Austrian checks appear to undermine the EU's Schengen system, which normally allows unrestricted travel. But in exceptional circumstances countries can reintroduce border controls under Schengen.
Austria's Interior Ministry told the BBC the checks would not be necessary if there were an agreement to distribute the migrants fairly.
The head of the European Union's police agency, Rob Wainwright, said catching people smugglers would be easier with more "effective" border controls but added that the Schengen system had pros and cons.
Five people have been detained in connection with the deaths of 71 people, most of them thought to be Syrians, in a lorry found last week on the A4 at Parndorf.
Austria was shocked by the gruesome nature of the deaths. Thousands rallied on Monday demanding better rights for migrants.
As well as the bodies in the lorry in Austria, hundreds more people drowned in the Mediterranean last week while trying to reach Europe from Libya.
10 days of the migrant crisis
- Crowds of migrants rush at Macedonian border forces in an attempt to enter from Greece
- Hundreds of people are feared dead after two boats carrying about 500 migrants sink in the Mediterranean, off Libya. More than 300,000 migrants have risked their lives trying to cross the Mediterranean this year, according to the UN
- A lorry abandoned near Parndorf in Austria is found to have 71 dead people inside including four children
- Twenty-six migrants are rescued from a van in Austria, near the border with Germany.
A record number of 107,500 migrants reached the EU's borders in July.
The UN says the continuing conflict in Syria is a major factor behind the rise in migrant numbers.
Greece, Italy and Hungary have particularly struggled with the surge of migrants from not only Syria but the rest of the Middle East and Africa.
An extraordinary meeting of EU interior ministers is to be held on 14 September.
Some governments have refused to take in refugees and resisted EU proposals to agree on a common plan.
Others are tightening their policies on asylum and border security, sometimes because of rising anti-immigration sentiment.
On Sunday France condemned Hungary for building a razor-wire fence along its border with Serbia to try to keep out migrants travelling north from Greece via the Balkans.
UK Home Secretary Theresa May blamed the Schengen system - which the UK did not join - for "exacerbating tragedies". She has demanded tighter EU rules on free movement.
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