Hundreds of left-wing protesters clashed with Italian police at the country's Austrian border on Saturday, leaving four officers injured as they fought against the proposed closure of the border between the two countries.
Italian riot police standing just 100 to 200 metres from the border responded with tear gas after a group of 50 to 80 anarchists, all covering their faces with motorcycle helmets and gas masks, threw bricks, firecrackers and other objects at a police blockade at the Brenner Pass.
On the other side of the border, hundreds of Austrian police were waiting to act, but were never deployed, as their Italian colleagues tried to contain the protest, which first spilled over on to the railway and then onto the busy Brenner highway.
As police pushed the protesters deeper back into Italian territory, many shed their helmets and gas masks, scampering up onto a steep hillside overlooking the highway and shouting at police to free their detained comrades.
According to La Republicca, eight Italians, two Austrians and a German were arrested during the demonstration, which saw more than 600 people gathered to protest against Austria's plans to erect a fence at the Brenner crossing it shares with Italy to 'channel' people.
Part of Europe's borderless Schengen zone, Brenner is one of the routes that migrants use as they head towards wealthy northern Europe.
Italian newspaper Corriera della Sera reported earlier this week that the protest had been organised by an anarchist group from Trentino, northern Italy, and was expected to attract demonstrators from abroad.
But their plans upset the town's mayor, who told La Republicca: 'This isn't a suitable place to protest, it is a peaceful area.
Austria planned to send 300 police officers to the protests but were 'ready to increase the number,' Tyrol police said, adding the Italian police were prepared to send the same number.
Austrian Interior Minister Wolfgang Sobotka said in Rome last month that as many as a million migrants were poised to cross the Mediterranean from Libya this year. Italy says the figure is much lower, though calm summer seas may well bring a surge.
Italy and Germany are utterly opposed to Austria's plan to build a fence at its border with Italy, Italian Prime Minister Matteo Renzi said on Thursday after talks with German Chancellor Angela Merkel.
The Alpine route is a major European transport corridor and a key link between the north and south of the continent, said Mr Juncker during an interview with Germany's Funke Mediengruppe.
'This is why everything that blocks the Brenner Pass will have not just serious economic consequences, but most importantly heavy political consequences,' he said.
With over 28,500 migrants arriving since January 1, Italy has once again become the principal entry point for migrants arriving in Europe, following a controversial EU-Turkey deal and the closure of the Balkan route up from Greece.
In previous years, many migrants landing in Italy have headed on to other countries including Austria but Rome now fears it could be stuck hosting thousands of new arrivals.
On average 2,500 lorries and 15,000 cars travel daily through the Brenner Pass - a crucial lifeline for Italy's exports to northern Europe that is already prone to delays even without border checks.
Austria sits at the crossroads of the two major migrant routes, from the Balkans and from Italy, and saw hundreds of thousands of migrants cross its territory in 2015.
Authorities have received around 90,000 asylum applications from people fleeing war, persecution and poverty who have opted to settle in the country.
Mr Juncker also raised the alarm over Austria's response to the migrant crisis which he said had tempted other countries to close their borders while making far-right politics 'presentable' elsewhere in Europe.
'What we see in Austria we have unfortunately seen in other European countries, where (political) parties play with people's fears,' he said.
Meanwhile on Saturday, the 1,759 migrants arrived in the Sicilian port of Augusta, after being rescued in 10 operations involving the Italian navy, coastguard and finance police, the European Union's external borders agency Frontex and the medical charity Medecins Sans Frontieres.
The latest arrivals picked up in the Strait of Sicily will bring the total of migrants reaching Italy by boat so far this year to more than 30,000, slightly higher than in the same period of 2015.
Officials fear the numbers trying to make the crossing to southern Italy will increase as sailing conditions improve in warmer weather.
More than 1.2 million Arab, African and Asian migrants fleeing war and poverty have streamed into the European Union since the start of last year.
Most of those trying to reach Italy leave the coast of lawless Libya on rickety fishing boats or rubber dinghies, heading for the Italian island of Lampedusa, which is close to Tunisia, or towards Sicily.
On Wednesday, however, Italy's coastguard said it had rescued 42 migrants from a sailboat off the coast of Puglia, in the southeastern heel of mainland Italy.