Hungary sealed its border with Serbia on Tuesday to stem the massive influx of refugees as Germany slammed the "disgraceful" refusal of other EU countries to accept more migrants after 22 died in yet another shipwreck.

Budapest's move came after Austria and Slovakian authorities followed Germany's lead in reimposing border controls, a further body blow to Europe's cherished passport-free Schengen zone as the EU's border agency said more than half a million migrants had been counted at the bloc's borders so far this year.

Honking cars with stressed drivers banked up for kilometers (miles) at an Austrian-German road crossing Monday, hours after Berlin reimposed border checks to control a massive refugee influx.

Two German police officers checked the identity papers of the steady stream of drivers and passengers on a bridge where the morning traffic bottle-necked into a single lane.

Germany said it was reinstating border controls on Sunday as Europe's top economy admitted it could no longer cope with a record influx of refugees.

The announcement came on the eve of a key EU meeting on the crisis, with interior ministers set to lock horns over a controversial plan to spread migrants across the continent.

Germany's Interior Minister Thomas de Maiziere said Sunday Europe should stop looking on helplessly as "murder" rages on in Syria, as he called on the bloc to review its strategy on the conflict.

"The fight against the Syrian dictator Assad and the so-called Islamic State has not been carried out with the necessary determination," he told the Tagesspiegel newspaper in an interview published Sunday.

Munich is at the limit of its capacity to welcome refugees arriving en masse in Germany, police warned Sunday, a day after 12,200 asylum-seekers reached the city. 

"We had a total of 12,200 refugees on Saturday... today we're expecting several hundreds. Given the numbers from yesterday, it is very clear that we have reached the upper limit of our capacity," said a police spokesman.

Progress has been made on some contentious issues in the peace process, the foreign ministers of Germany, Russia, Ukraine and France said after holding talks in Berlin on Saturday to prepare for a summit in Paris on October 2.

Germany's top diplomat, Frank-Walter Steinmeier, said the meeting had been "less confrontational" than previous ones and that the warring sides were now "very close" to an agreement on withdrawing heavy weapons from the frontline.

A former French minister stirred up controversy Friday after saying Germany "took our Jews and gave us Arabs" as France began taking some of the thousands of refugees arriving in Germany. 

Patrick Devedjian, a right-winger who served in the governments of presidents Jacques Chirac and Nicolas Sarkozy, made the remark at a press conference, but quickly tried to backtrack on social media. 

Eastern European countries rejected migrant quotas on Friday, exposing a deep rift on the continent over how to respond to the crisis as new footage raised further questions about Hungary's treatment of floods of refugees.

Pressing his Czech, Hungarian, Polish and Slovakian counterparts in Prague, Germany's foreign minister warned that the influx of hundreds of thousands of migrants could be "the biggest challenge for the EU in its history."

Muslim radicals in Germany are trying to recruit some of the growing numbers of asylum seekers reaching the country, according to intelligence services quoted by the German news agency DPA.

The Islamic extremists "are trying to approach the young unaccompanied refugees, who arrive in our country without their families and are particularly looking for contacts and support," a spokesman for the intelligence service in the southern state of Bavaria told DPA.

Progressive Socialist Party chief MP Walid Jumblat sought on Thursday to limit any possible tension that could emerge over the killing of Sheikh Wahid al-Balous, a prominent Druze cleric in Syria.

“This is not an opportunity to challenge anyone. We respect all viewpoints,” said Jumblat at the memorial service of al-Balous held at the Druze Community House in Beirut's Verdun district.