Wall Street stocks tumbled, joining European equities in falling on worries about global growth and the burgeoning Volkswagen emissions scandal.
France's finance minister called for a "Europe-wide" probe after revelations that hundreds of thousands of Volkswagen diesel cars had software that secretly thwarts US pollution tests.
German Foreign Minister Frank-Walter Steinmeier said that EU members reluctant to accept migrant quotas may have to be outvoted and overruled in the 28-member bloc.
EU president Donald Tusk said he would consider requests by German Chancellor Angela Merkel and others for an emergency summit on migrants and decide later this week.
German Chancellor Angela Merkel urged the EU to agree to a proportional distribution of refugees with no limits on actual numbers, going much further than plans unveiled by the European Commission.
Germany's Interior Minister Thomas de Maiziere said 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.
Ukrainian Prime Minister Arseniy Yatsenyuk criticised as "anti-Ukrainian and anti-European" a deal between Russia's energy giant Gazprom and several Western firms to build a second gas pipeline under the Baltic Sea.
Chancellor Angela Merkel won a hero's welcome as she visited a Berlin migrant centre, with Syrians cheering and taking selfies as Germany threw open its doors to thousands of refugees.
Around 450,000 refugees have arrived in Germany so far this year, including 37,000 in the first eight days of September, Vice Chancellor Sigmar Gabriel told parliament.
The leaders of France, Germany, Russia and Ukraine agreed to hold an October summit on ending the conflict in Ukraine.
A first group of around 50 refugees arrived in France from Germany as Paris tries to ease pressure on its neighbour, which has received the bulk of the migrants streaming into Europe.
German Chancellor Angela Merkel said a European Commission plan to relocate refugees from overstretched EU states was "an important first step".
Denmark has sent back a first group of refugees who arrived from Germany, Danish police said Tuesday, with others expected to follow.
Germany readied for hundreds more refugees to arrive from Hungary via Austria, a day after thousands were greeted, often by volunteers holding signs that read "Welcome to Germany".
The Canadian IBF middleweight champion David Lemieux soon facing the undefeated Kazakhstani Gennady Golovkin has, too, taken the Borat reference.
"We love Germany," several young migrants yelled happily as they stumbled out of a train in Munich -- the last stop, they hope, of their long and perilous journey from war.
Berlin pledged to send police reinforcements to the eastern German town hit by violent anti-migrant protests.
German Chancellor Angela Merkel faced down far-right hecklers vowing zero tolerance for "vile" anti-migrant violence as rescuers found 55 corpses on stricken boats in the Mediterranean.
German Chancellor Angela Merkel will visit a refugee centre hit by violent far-right protests, a day after Berlin said it had eased some asylum rules.
German Chancellor Angela Merkel and French President Francois Hollande called for a "unified" response to the worst refugee crisis to hit the EU since World War II.