The United Nations' refugee agency has called on Europe to band together in dealing with the ongoing migrant crisis following chaotic scenes on the weekend in Greece, Macedonia and Serbia. More capacity is required to ensure the safety of migrants on their journey to other parts of Europe, according to a statement Sunday night from the United Nations High Commissioner for Refugees (UNHCR).

An estimated 7,000 migrants arrived in Serbia in the night to Sunday after neighboring Macedonia caved into pressure and opened its borders following clashes with police on Friday. UNHCR plans to build more reception centers for refugees at the border region, according to the statement. The organization also criticized Athens for failing to register migrants before entering Macedonia.

Other European Union member states must also step up to help, according to UNHCR Europe Bureau Director Vincent Cochotel, who said the problem "will not go away any time soon and affects all of Europe."

Italian Foreign Minister Paolo Gentiloni also warned on Sunday that a deepening immigration crisis is threatening to rip the "soul" out of the European Union. In a hard-hitting interview, Paolo Gentiloni said the kind of chaotic scenes witnessed this weekend at the Greece-Macedonia border represented a real threat to the free movement of people across the bloc.

"On immigration, Europe is in danger of displaying the worst of itself: selfishness, haphazard decision-making and rows between member states," Gentiloni told Il Messaggero. "I am very worried. Today it is on this issue that Europe will either rediscover its soul or lose it for good." Gentiloni urged Italy's EU partners to stop squabbling and start working on a common solution to the crisis. The alternative, he warned, would be the inevitable collapse of the Schengen accords that allow free travel across much of continental Europe. "What is at risk is one of the fundamental pillars of the European Union: the free circulation of people," the minister said. "From the Sicilian coast to Kos, from Macedonia to Hungary and at Calais, tensions are mounting and, over time, they could put Schengen in question. Can we imagine a union without Schengen? A return to the old borders? Migrants are not arriving in Greece, Italy or Hungary. They're arriving in Europe. That is why the reception rules have to be 'Europeanized'."

In Germany, meanwhile, the Vice Chancellor and Foreign Minister Frank-Walter Steinmeier, a fellow Social Democrat, issued a joint call for the EU's asylum policy to be revamped. "It is necessary to share out refugees in Europe fairly," the two said in the Sunday edition of the Frankfurter Allgemeine newspaper. They also called for a "European asylum code" that would guarantee EU-wide asylum status.

EU interior and foreign ministers will discuss the migrant crisis in mid-October, ahead of a summit in Malta in November, French Interior Minister Bernard Cazeneuve said Thursday.