ROME (Reuters) - Italy and Austria on Thursday played down tensions that flared after Austria said it might reintroduce border controls at the Alpine Brenner pass to keep migrants from coming from Italy.

A sign reading "Republic of Austria - border control" is seen at Brenner on the Italian-Austrian border, Italy, April 12, 2016. Picture taken April 12, 2016. REUTERS/Dominic Ebenbichler

A day after Italian Prime Minister Matteo Renzi said Austria’s announced plans to build a fence at Brenner was “shamelessly against European rules”, Austria’s new Interior Minister Wolfgang Sobotka said he had come to Italy “to calm tempers”.

Both Italy and Austria are members of the European Union’s Schengen open-border zone, but free movement has been jeopardized by the reimposition of controls at some key crossings by countries affected by the migrant influx.

“There will be no wall,” Sobotka told reporters after meeting his counterpart Angelino Alfano. “If and only if it is necessary will we introduce more controls (at Brenner) by slowing traffic and trains ... but circulation will be guaranteed.”

Any toughening of border controls at the Brenner Pass would slow traffic on an important route from Italy to Germany, Italy’s top trading partner.

Hundreds of thousands of migrants fleeing war and poverty in the Middle East and Africa have crossed the Mediterranean to Italy since 2014, and Austria has said Rome must stop them from traveling on toward northern Europe.

On Wednesday, Austria outlined plans to erect a 370 meter-long fence at the Brenner Pass, which is the busiest route through the Alps for heavy goods vehicles, but Sobotka said on Thursday it would be used only to “channel” people and was not a barrier.

Austria’s governing coalition of Social Democrats and the conservative People’s Party announced the fence plan after the anti-immigration Freedom Party’s candidate secured a record share of the vote in Sunday’s presidential election.

“We worked to save the right to circulate at Brenner, to clarify issues and avoid a crisis with Austria,” Alfano told reporters after the meeting. “There’s no need for any kind of barrier at Brenner.”

Sobotka told Alfano that “preparations are under way in case there is an extraordinary surge of migrants”, Alfano said.

Sobotka said as many as a million migrants in Libya were poised to cross the sea to Europe this year. Italy says the true figure is much lower, but arrivals are expected to surge during the summer months.

Some 27,000 migrants have arrived in Italy by boat this year, the Interior Ministry says, and the coastguard said 600 were rescued on Thursday.

Alfano defended Italy’s handling of Europe’s biggest migration crisis since World War Two, saying police were now fingerprinting all migrants in “hotspots” co-managed with the EU.

But Alfano also said for the first time that Italy might have to create closed holding centers for migrants who are not seeking asylum or who do not qualify for it, so they can be repatriated.

“In Europe and obviously not only in Italy, there have to be some centers in which irregular migrants must wait to be repatriated without being able to escape,” Alfano said.