Volkswacht Bodensee - Germany's far-right AfD holds march after Christmas market attack

Meanwhile, an anti-extremist initiative called "Don't Give Hate a Chance" was gathering nearby in the eastern city of Magdeburg, which was mourning five dead and more than 200 injured in Friday's carnage.

"Terror has arrived in our city," said the AfD's leader in Saxony-Anhalt state, Jan Wenzel Schmidt, condemning what he labelled the "monstrous political failure" that led up to the attack, over which a Saudi man was arrested.

"We must close the borders," he told hundreds of supporters of the anti-immigration party. "We can no longer take in madmen from all over the world."

The party's co-leader Alice Weidel demanded "change so we can finally live in security again", as people in the crowd chanted: "Deport, deport, deport!"

The anti-AfD initiative said in a message that "we are all shocked and angry to see that people want to exploit this cruel act for their own political ends" and called for "tolerance and humanity".

As Germany has mourned the dead -- four women and a nine-year-old boy -- Chancellor Olaf Scholz's government has faced angry questions on possible errors and missed warnings about the Saudi suspect arrested at the scene of Friday's attack.

Those concerns were fuelled by news that Saudi Arabia had warned Germany about its citizen Taleb al-Abdulmohsen, 50, who came to Germany in 2006 and was granted refugee status 10 years later.

Riyadh had warned Berlin "many times" that the psychiatrist and activist "could be dangerous", a source close to the Saudi government told AFP, adding that "there was (an extradition) request".

- Puzzled by motive -

Police were still puzzling over why the driver smashed a rented SUV at high speed through the crowd of revellers, bringing death and chaos to the festive event.

Abdulmohsen had in his many online posts voiced strongly anti-Islam views, anger at German authorities and support for far-right conspiracy narratives on the "Islamisation" of Europe.

Die Welt daily, citing unnamed security sources, reported that Abdulmohsen had been treated for a mental illness in the past, but this has not been confirmed by authorities.

The Saudi suspect has been remanded in custody in a top-security facility on five counts of murder and 205 of attempted murder, prosecutors said, but not so far on terrorism-related charges.

Even as the attacker's motive remained unclear, the attack has moved the flashpoint issues of security and immigration back to the centre of German politics ahead of February 23 elections.

The mass-circulation Bild daily wrote that "although the background to the terrible attack in Magdeburg has not yet been clarified, it is already clear: there will be a 'before' and an 'after' in this election campaign."

- 'Weakest link' -

Interior Minister Nancy Faeser has vowed that "no stone will be left unturned" in shedding light on what information had been available on Abdulmohsen in the past.

She stressed that the attacker did "not fit any previous pattern" because "he acted like an Islamist terrorist although ideologically he was clearly an enemy of Islam."

The Association of German Criminal Police Officers warned that "it is still too early to draw hasty conclusions or even to formulate political demands".

German Christmas markets -- among the country's most iconic and beloved festive events -- have been specially secured since a jihadist attacker rammed a truck through one in Berlin in 2016, killing 13 people.

Police have also stepped up weapons checks following several deadly knife attacks, including one that killed three people and wounded eight at a summer festival in the western city of Solingen.

The suspect, a 26-year-old Syrian man with suspected links to the Islamic State group, had evaded attempts to deport him.

The Magdeburg market too had been secured with police and heavy barricades, but the attacker managed to exploit a five-metre gap when he steered his rented BMW sport utility vehicle into the site and then raced into the unsuspecting crowd.

"A security concept is only as strong as its weakest link," counterterrorism expert Peter Neumann told news weekly Der Spiegel. "If one entry point remains unprotected, all the other concrete bollards are of no use."

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R.Braegger--VB