The Slovenian government has said the checks should last for at least 10 days.
Ljubljana officially introduced border checks with neighbouring Hungary and Croatia on Saturday following a similar move made by Italy due to an upsurge of violence in the Middle East.
Italy's far-right government also suspended an open-border agreement with Slovenia effective from Saturday for 10 days.
The announcement reflects increasing security concerns in Europe due to the war between Israel and the Hamas militant group. On Thursday, European Union interior ministers debated how to manage the impact of the war on the 27-nation bloc after a firebomb assault on a Berlin synagogue and separate killings in Belgium and France by suspected Islamic extremists.
Securing the Schengen Area
EU Home Affairs Commissioner Ylva Johansson said in Luxembourg that the commission is looking into the issue of internal border checks, which she described as one of the challenges of the Schengen area.
“Even if it is justified by severe things, internal security or illegal border crossing, internal border controls also hamper free movement,” said Johansson. “We need to avoid it."
The shooter in the Belgian attack, a Tunisian national, had been denied residency in four European countries and was issued a deportation order from Belgium in 2021, but disappeared from sight. It was only after he killed two Swedish men on Tuesday, that officials were able to track him down. He was shot dead by police as they tried to arrest him.
Slovenia's Interior Minister Boštjan Poklukar presented the details at the EU meeting in Luxembourg. He said authorities are expected to set up special checkpoints for EU citizens and local residents living in the border area.
Slovenia, Italy, Croatia and Hungary are all among the 27 countries that belong to the Schengen area, the world’s largest free travel zone. The Schengen nations can temporarily reintroduce border controls “in the event of a serious threat to public policy or internal security.”
Croatia and Hungary react
Péter Szijjártó, the foreign minister for Hungary's staunchly anti-immigration government, attributed Slovenia's decision to EU immigration policies that he said were endangering both the physical security and economic prosperity of European countries.
“Europe’s economy is suffering as border controls within the Schengen area hinder and slow down trade and the cross-border operations of businesses,” Szijjártó wrote on Facebook. “If Brussels does not change its migration policy, we could find ourselves where we do not want to be: in an era of Europe torn apart by old borders.”
In Zagreb, Croatia's Prime Minister Andrej Plenković expressed hope that the decision would be temporary. Such measures are not new, Plenković added, and are the result of “increased migration movement and (or) terrorism threat.”
“It must remain an exception,” said Plenković.
Italy's right-wing government on Wednesday said authorities in the northeastern border region of Friuli-Venezia Giulia had identified 16,000 people so far this year who had entered Italy illegally across the Slovenian border.
Other countries that are introducing border checks within Europe's Schengen area include Denmark and Sweden, while France intends to keep checks in place until at least May 2024.