The latest news on the influx of asylum-seekers and other migrants in Europe. All times local.

3:35 p.m.

The U.N. refugee agency is warning that aid groups face a massive challenge to help up to 1.5 million civilians in the northern Iraqi city of Mosul under the control of the Islamic State group.

UNHCR Baghdad representative Bruno Geddo said Tuesday that "the mother of all battles is going to be in Mosul."

He said before talks in Brussels with European officials that the Iraqi city is contaminated with mines and booby-traps, and that this will hamper any efforts to provide relief.

But Geddo said problems are likely to start first in Fallujah, western Iraq, where some 200,000 civilians are living and IS has been operating.

He warned that many Iraqis remain determined to leave, saying that "when you flee for your life there is no amount of discouragement that can make you go back."


3:30 p.m.

Austria's interior ministry says the country will tighten entry requirements later this week for migrants by only letting in those seeking asylum in Austria or neighboring Germany.

Ministry spokesman Karl-Heinz Grundboeck said Tuesday the restriction will be implemented as of Friday. As of then, migrants coming in can do so only at the main Spielfeld crossing with Slovenia.

With most migrants who enter Austria already planning to stay there or to proceed to Germany, it is unclear whether the restriction will greatly reduce the flow.

Austria already re-imposed controls in September on its border to Slovenia, from where migrants have been entering since Hungary sealed its borders in the summer to those heading westward toward prosperous EU countries. But the move may mean a greater police and military presence.


3:15 p.m.

The four Central European members of the European Union have reconfirmed their fierce opposition to a plan to redistribute 120,000 asylum-seekers among the bloc's 28 nations and called for the strict control and registration of all refugees on the external border of the EU visa-free Schengen zone.

Representatives of the Czech Republic, Hungary, Poland and Slovakia, who form an informal grouping known as the Visegrad Four or V4, say they are united against the plan.

Czech Interior Minister Milan Chovanec, who hosted Tuesday's meeting says: "The V4 countries still reject the system of compulsory quotas for relocation."

Slovakia and Hungary have already legally challenged the system.

In another disagreement with Brussels, the four also refused a recent EU proposal to tighten the gun-control rules following the Paris attacks.


3 p.m.

Officials from Slovenia and Serbia have warned that if Austria scales down the influx of refugees into the country that would cause a domino effect and tensions down the so-called Balkan migrant corridor.

Slovenian Foreign Minister Karl Erjavec and Serbian counterpart Ivica Dacic called Tuesday for a joint EU-backed plan to manage the crisis before an expected surge in the number of Europe-bound migrants in spring.

Erjavec says "we can expect some states to introduce stricter controls on their borders, which means countries in the western Balkans could become a pocket." Erjavec says Austria has announced new measures for this week.

Dacic says migrants won't be allowed to return to Serbia if turned back elsewhere. He warns of a "collapse" if case of a Balkan bottleneck.