European countries have “eight to six weeks” to save the Schengen system of border-free travel, Dutch prime minister Mark Rutte warned at the World Economic Forum in Davos, Switzerland on Thursday.

Once spring sets in, refugee flows from the Middle East are likely to increase. Already, numbers are higher this month than they were in January of last year and 2015 saw the highest number of people traveling into the European Union since the bloc removed its internal border controls.

“We cannot cope with the numbers any longer,” Rutte said.

He called for a strengthening of the European external frontier and rapid agreement on sharing immigrants around the EU.

Border controls

Several member states have already suspended Schengen, including Austria, which this week also announced it would cap asylum claims at 37,500 for whole of 2016.

A tougher Austrian border policy could ease the burden on neighboring Germany, which received some one million immigrants last year from the Balkans, the Middle East and North Africa.

Germany has erected temporary border checks. Thomas de Maizière, the interior minister, said these were unlikely to be lifted soon.

Chancellor Angela Merkel is under pressure from her own right-wing supporters to restrict immigration further. Since foreigners were implicated in mass sexual assaults in Cologne and other German cities on New Year’s Eve, the mood in Germany has shifted. One in two Germans now favor following Austria’s example and capping the number of immigrants for 2016.

Denmark, Croatia, Slovenia and Sweden are among other countries that have restricted access to some extent.

Hungary, under the nationalist premier Viktor Orbán, has gone furthest, fencing off its southern borders and citing the high levels of immigration as a reason for implementing several restrictive measures, including allowing police to conduct searches without warrants and enlisting telecom companies in the collection of bulk phone data.

Blaming Greece

Earlier this month, Morgan Johansson, the Swedish migration minister, and Ole Schröder, a lawmaker for Germany’s ruling conservative party, pointed the finger at Greece, which they said had failed to control the outer border.

Sweden registered 160,000 asylum seekers last year, the highest per-capita ratio in the EU.

For almost all of 2015, Greece refused to call in help from Frontex, the European border agency, and accept humanitarian aid. Only after warnings that it could be ejected from the Schengen Area did the country allow foreign staff to help guard its Aegean Islands and the northern border with Macedonia in December.

Speaking alongside Rutte in Davos, Greek prime minister Alexis Tsipras called for a European solution to the migrant crisis.

But the vast majority of member states have rejected a European Commission proposal to spread refugees proportionately across the bloc while border nations like Greece and Italy have failed to uphold their treaty obligation to register and process all asylum seekers who arrive on their shores.