Content warning: This article contains details of violence and a fatal attack that may be distressing to some readers. Reader discretion is advised.

Austrians were placing candles Sunday on the site of a stabbing that left a teenager dead and five other people injured, shaking the Alpine nation after this week's collapse of government talks where immigration and security were major issues.

A Syrian asylum seeker, 23, was arrested just after Saturday's attack in the southern city of Villach, which a fellow Syrian food deliverer stopped by ramming a car into the attacker, according to police.

Residents were placing candles in front of shops in a street, where the attack happened in the center of Villach, a city in Carinthia province.

"I am afraid for my children. I am afraid for those around me. I fear for the future. I fear where this will lead. I am endlessly sad," local resident Tanja Planinschek told AFP at the site.

"Not only I, but all of us have been afraid for a long time that something bigger will happen," she said, adding the country "should open our eyes and see whom we let in, whom we help, whom we leave with all kinds of freedoms. If nothing is done, it will get even worse."

'Couldn't let that happen'

On Saturday, a man "randomly" attacked passers-by with a knife, police said.

A 14-year-old boy died, while five other men -- the oldest 36 year old -- were hurt, including two seriously.

A food deliverer -- also from Syria -- intervened, ramming his car into the attacker, who was slightly hurt, police said.

"I saw a person lying on the ground, a man was attacking other passers-by – I didn’t think twice and drove at him," the Krone tabloid quoted the deliverer, Alaaeddin Alhalabi, 42, as saying. 

"He wanted to go towards the city center, there were children on the street –- I couldn't let that happen," he said, adding he regretted he could not save the 14-year-old.

The suspect is an asylum seeker with a valid residence permit and no criminal record, according to preliminary information, according to police.

Police said they could not yet say anything about the motive of the attack, but were verifying eyewitness accounts that the attacker had shouted "Allahu Akbar" (God is greatest).

"First, he argued with people in a side street, then he started hitting around him. We first tried to hold him down. Then we saw the knife and backed away," another eyewitness, Mahir, 29, told Krone. "It was like a movie. He went after everyone."

'Harshest consequences'

Interior Minister Gerhard Karner was to travel to Villach on Sunday.

Carinthia Governor Peter Kaiser of the Social Democrats called for the "harshest consequences" for this "unbelievable atrocity".

Far-right leader Herbert Kickl -- whose party topped September's national elections for the first time ever -- said he was "appalled" by the attack, calling for "a rigorous clamp-down on asylum".

Kickl's Freedom Party (FPOe) this week failed in talks to form a government with the runner-up and incumbent conservatives because of disagreements -- among others -- over who would hold sensitive cabinet posts dealing with security.

Austria hosts a large Syrian refugee population of almost 100,000.

After Bashar al-Assad's ouster in Syria in December, Austria and several European countries froze pending asylum requests from Syrians to reassess the situation.

In addition, Austria has stopped family reunifications and sent out at least 2,400 letters to revoke refugee status.

The interior ministry has said it is preparing "an orderly repatriation and deportation program to Syria".

Austria has so far only seen one jihadist attack, in 2020, when a convicted IS sympathizer went on a shooting rampage in downtown Vienna, killing four.

The Villach attack comes just two days after a suspected Afghan asylum seeker rammed a car into people in the city of Munich in neighboring Germany, killing a two-year-old girl and her mother and wounding 37 other people.

A 24-year-old Afghan asylum seeker was arrested on suspicion of deliberately driving the car into a trade union demonstration. German police said he may have had Islamist extremist motives for the attack.

The carnage came shortly before Germans head to the polls for a February 23 election where immigration is a key issue following a spate of attacks blamed on migrants.

Austria's Interior Minister Gerhard Karner on Sunday said that a stabbing that left a teenager dead and five others injured in southern Austria was an "Islamist attack".

"It is an Islamist attack with IS connections," Karner told reporters in the southern city of Villach where Saturday's attack took place, adding that the suspect -- a 23-year-old Syrian asylum seeker -- was radicalized online "in a short space of time".