Amid concerns related to extremist violence and illegal migration, several European Union (EU) countries, part of the Schengen area that typically allows free movement, have recently heightened their border controls.
On Thursday, Croatian Prime Minister Andrej Plenkovic announced temporary reintroduction of border controls with Slovenia, hours after the Slovenian government decided to implement border controls with Croatia and Hungary from Saturday till October 30, reports Xinhua news agency.
"There is a need for immediate action to ensure public order and security of our citizens as well as the citizens of the European Union," the Slovenian government said in a statement.
"Outside events confirm that members of various terrorist and extremist movements and groups are withdrawing from the areas of armed conflicts to avoid possible consequences for their deeds, or even with an intent to endanger our security and stability."
The statement said Slovenia had registered 48,076 illegal border crossings from the start of the year until October 15, compared to 18,433 illegal crossings in the first nine months of 2022.
On Wednesday, Italy temporarily suspended the EU's Schengen rules for open travel, reactivating dormant border controls with Slovenia.
On the border between Italy and Slovenia, controls will begin on Saturday and last for at least 10 days, said the Italian government, adding that the goal is a "rapid return" to control-free border crossings, but the measure could be extended.
"The suspension of the Schengen Treaty on free movement in Europe was necessary due to the worsening situation in the Middle East, the increase in migratory flows along the Balkan route, and above all for reasons of national security," Italian Prime Minister Giorgia Meloni said on social media.
Germany on Monday also notified the European Commission of temporary controls at its borders with Poland, the Czech Republic and Switzerland in an effort to fight illegal migration.
The decision came as "the business of traffickers is becoming increasingly brutal and unscrupulous", said German Interior Minister Nancy Faeser.
By the beginning of October, Germany had already detected 98,000 unauthorised entries, 6,000 more than in the whole of last year.
The introduction of these border restrictions came at a time that multiple European countries have recently seen a surge in public security incidents.
After a 45-year-old gunman of Tunisian origin shot dead two Swedish citizens in the center of Brussels on Monday evening, Belgian authorities raised the terror threat level for the whole country.
On Tuesday, Italy arrested two people suspected of recruiting for the Islamic State terrorist group.
Italian Foreign Minister Antonio Tajani downplayed the immediate threat of a terror attack in Italy, but said it was important for the country to remain vigilant.
Moreover, a number of European airports received bomb threats in last few days.
According to French police, at least seven airports received threats and were evacuated on Thursday, including those in Lille, Lyon, Bordeaux, Nantes and Toulouse.
A bomb threat also triggered the evacuation of Ostend-Bruges Airport in northwestern Belgium on Wednesday.
The ongoing war in Gaza has strained the nerves of many European countries, especially France and Germany, which are home to the EU's largest Jewish and Muslim communities.
As the Hamas-Israel conflict entered into the second week, there is still no end in sight. It's uncertain how long the Schengen countries will maintain such border controls or whether more countries will follow suit.
Addressing a press conference on Thursday, Croatian Prime Minister Plenkovic said: "Schengen is not finished, but it has a problem. The introduction of border controls is not a novelty, it comes about due to migration trends and assessments of increased security threats due to terrorism."