BERLIN (Reuters) - European Commission President Jean-Claude Juncker aims to get a group of EU leaders attending a summit on Sunday to agree short-term steps to tackle the migrant crisis in the western Balkans.

Migrants as they make their way on foot after crossing the Croatian-Slovenian border, in Rigonce, Slovenia, October 22, 2015. REUTERS/Srdjan Zivulovic

As winter approaches, concern is growing for hundreds of thousands of migrants who are camped outside in western Balkan countries after arriving in Europe, many from Middle East war zones such as Syria.

Juncker has summoned European Union leaders from the region and Chancellor Angela Merkel of Germany, which is taking in more refugees than any other EU state, for talks on Sunday.

“They will discuss urgently needed, common operative answers to the current humanitarian demands and decide on short-term measures,” Juncker told German media group Funke, adding closer cooperation was needed to master the crisis.

The situation for migrants deteriorated after Hungary sealed its borders with Serbia and Croatia, leaving many stranded in other overwhelmed states.

German media have reported that Juncker will present a 16-point plan, including an undertaking not to send migrants from one country to another without prior agreement.

Slovenia, where 58,000 migrants have arrived in the last week, said on Saturday that it expected an “immediate operational response of the EU” following the meeting, which its prime minister Miro Cerar will attend.

Der Spiegel magazine meanwhile reported that the EU wanted to accelerate talks on Turkey’s bid to join the bloc, saying it was preparing a possible opening of a chapter on justice, human rights and the rule of law. Merkel, previously opposed to Turkish membership, has embraced Ankara as a partner in the refugee crisis.

Juncker also praised Merkel for ignoring public opinion in her efforts to tackle the refugee crisis, which she describes as a bigger challenge for Europe than Greece’s debt woes.

“This isn’t about short-term popularity but about substance,” Juncker told the Funke group.

Germany is struggling to cope with an expected 800,000 or more migrants this year, almost 1 percent of its population.

Merkel’s popularity has dropped since she threw open the doors to Syrian refugees nearly two months ago -- a move which also angered some in her conservative bloc. Amid fears of growing right-wing radicalism, support is growing for the anti-immigrant Alternative for Germany (AfD).

Some 150 AfD supporters gathered outside the headquarters of Merkel’s Christian Democrats (CDU) in Berlin on Saturday, waving placards saying “Red Card for Merkel” and “Thank you, Hungary”.

Finance Minister Wolfgang Schaeuble was quoted in Der Spiegel as saying the mood among conservatives was “dramatic” and that her CDU faced a tough test if the latest measures to ease the situation in Germany did not help.

A new law to speed up asylum procedures and deportation for migrants from southeastern Europe took effect on Saturday.

There are also worries about the influx of migrants pushing up unemployment in Europe’s biggest economy although some economists say they will provide a new supply of labor as Germany’s population ages and so boost economic growth.

In her weekly podcast, Merkel said many of those arriving in Germany would have a tough time. “There will be a proportion who don’t have such a good education and we must make sure that they quickly find work, especially young people.”

Migrants with good chances of staying can join integration courses to learn German with 600 hours of lessons, she said.