The suspect in the attack on the Christmas market in Magdeburg appeared to be dissatisfied with the treatment of Saudi refugees in Germany, a prosecutor has said.
On Friday evening, a car was driven at speed into visiting crowds in the central German city.
Five people have died so far - including a nine-year-old child and four adults - with at least 200 more injured, according to authorities. Of those injured, 41 are said to be seriously hurt.
The suspect - who was arrested at the scene - was a 50-year-old Saudi citizen who worked as a doctor and arrived in Germany in 2006, premier of Saxony-Anhalt state Reiner Haseloff said.
He has been named as Taleb A in German media, although this has not been confirmed by German authorities.
Police director Tom-Oliver Langhans told a news conference on Saturday the attack had left the city "very alarmed".
He added that officers arrested the suspect three minutes after the first emergency calls were made from the market.
Prosecutor Horst Walter Nopens said the motive behind the attack appeared to be "dissatisfaction with the treatment of refugees from Saudi Arabia and how they are being treated in Germany".
German interior minister Nancy Faeser has said the suspect was Islamophobic.
The suspect has described himself as an "ex-Muslim" who sought asylum after receiving death threats for denouncing his faith.
His social media pages, which he posted on in the hours leading up to the attack, promote anti-Islam views - and claim Germany is allowing the "Islamisation of Europe".
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What we know about the attack so far
Video shows suspect being arrested
The suspect, who says he works as a psychiatrist at a government hospital, has appeared in various media reports about his efforts to help other former Muslims flee Saudi Arabia and other Gulf nations.
Tamara Zieschang, the state's interior minister, told reporters the suspect had been practising medicine in Bernburg, around 25 miles south of Magdeburg.
He has a website that he told the BBC in 2019 has helped "hundreds of people" seek asylum overseas.
The homepage reads: "My advice: do not seek asylum in Germany."
In videos with voiceovers in English, he claims he is being pursued by German police, who "sent someone carrying a knife to steal a USB stick from my mailbox".
Tweets supporting Elon Musk and Tommy Robinson
Another tweet criticises a commentator for saying X owner Elon Musk and far-right activist Tommy Robinson should be arrested.
He claims they "cited Germany as a shining example of media censorship", and adds: "My experience in Germany leaves no doubt - they actually censor victims."
German terrorist expert Professor Peter Neumann described the suspect's profile as unusual.
He says he "loves the AfD [Alternative for Germany] and wants to punish Germany for tolerance towards Islamists", the director of King's College London's International Centre for the Study of Radicalisation wrote on X.
Professor Neumann said: "After 25 years in this 'business' you think nothing could surprise you anymore... that really wasn't on my radar."
(c) Sky News 2024: Christmas market suspect may have been 'dissatisfied with treatment of Saud
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