On Friday evening, a man drove a car into a crowd of shoppers at a Christmas market in the German city of Magdeburg.
The attack killed five people, including a nine-year-old boy, and left more than 200 injured, many of them critically.
A judge has remanded a 50-year-old man in custody on suspicion of carrying out the attack.
Police believe he acted alone.
How did the attack unfold?
At 19:02 local time (18:02 GMT) the first call to emergency services was made.
The caller reported that a car had plowed into a crowd at a downtown Christmas market.
The caller assumed it was an accident, police said, but it soon became clear that was not the case.
The driver, police said, used traffic lights to veer off the road and onto a pedestrian crossing, driving him through an entry point to the market that is reserved for emergency vehicles, injuring a number of people along the way.
Unverified footage on social media showed the driver speeding the car across a footpath between Christmas stalls.
Eyewitnesses describe jumping out of the way of the car, running away or hiding.
Police said the driver then returned to the road he had entered and was forced to stop in traffic. Officers who were already at the market were able to detain and arrest the driver here.
Footage shows armed officers confronting and arresting a man who can be seen lying on the ground next to a stationary vehicle – a black BMW with significant damage to the front bumper and windscreen.
The entire incident was over in three minutes, police said.
Who are the victims?
A nine-year-old boy and four women aged 45, 52, 67 and 75 were confirmed dead in the attack.
More than 200 people were injured, with at least 41 of them in critical condition.
The death toll was previously reported as two dead and 68 injured, but was revised to a much higher total on Saturday morning.
None of the victims have yet been identified.
Who is the suspect?
The suspect has been identified in local media reports as Taleb al-Abdulmohsen, the BBC understands.
He is a 50-year-old psychiatrist born in Saudi Arabia who lives in Bernburg, about 40 km (25 miles) south of Magdeburg.
He is being held on suspicion of five murders, multiple attempted murders and grievous bodily harm, police said.
The motive behind the attack remains unclear, but authorities have said they believe he carried out the attack alone.
Al-Abdulmohsen arrived in Germany in 2006. and in 2016 was recognized as a refugee.
The suspect ran a website aimed at helping other ex-Muslims escape persecution in their Gulf homeland, and was interviewed about it by the BBC in 2019.
German Interior Minister Nancy Feiser told reporters it was “clear to see” that the suspect had “Islamophobic” views.
On social media, he is an outspoken critic of Islam and promotes conspiracy theories about an alleged plot by German authorities to Islamize Europe.
He also expressed sympathy on social media for Germany's far-right political party, the Alternative for Germany (AfD), by retweeting posts from the party's leader and a far-right activist.
Magdeburg police chief Tom-Oliver Langhans said police had previously assessed whether the suspect might have posed a potential threat, “but that discussion was a year ago”.
Feiser told German newspaper Bild that investigators would examine “in detail” what information authorities had about Al-Abdulmohsen in the past and how he was investigated.
Germany's migration and refugee agency said in a social media post that it had filed a complaint against the suspect, which it “took seriously,” but since the agency is not an investigative body, it referred the complainant to other authorities.
One tip received by authorities is believed to come from Saudi Arabian authorities.
A source close to the Saudi government told the BBC it had sent four official notifications, known as “Notes Verbales”, to German authorities warning them of what they said were the “very extreme views” held by Al-Abdulmohsen.
However, a counter-terrorism expert told the BBC that the Saudis may have orchestrated a disinformation campaign to discredit someone who tried to help young Saudi women seek asylum in Germany.
The head of the Federal Criminal Police Office (BKA), Holger Münch, told public broadcaster ZDF that his office received a notification from Saudi Arabia in November 2023. He said the local police had taken appropriate investigative measures, but the matter was inconclusive.
He added that the suspect “had various contacts with the authorities, insulted them and even made threats, but was not known for acts of violence.”
ReutersWhat did officials say about the attack?
“The reports from Magdeburg give rise to the worst fears,” German Chancellor Olaf Scholz said on social media platform X.
Magdeburg city councilor for public order Ronny Krug said the Christmas market would remain closed and that “Christmas in Magdeburg is over,” according to German public broadcaster MDR.
This sentiment was reflected on the market's website, which after the attack only showed a black screen with words of mourning announcing that the market had closed.
The Saudi government expressed “solidarity with the German people and the families of the victims” in a statement on X and “reaffirmed its rejection of the violence”.
UK Prime Minister Sir Keir Starmer said he was “appalled by the brutal attack in Magdeburg”, adding that his thoughts were with “the victims, their families and all those affected” in an X post on Friday night.