Hundreds of people are pausing at a make shift memorial in Berlin near the site of Monday's attack that killed 12 and injured at least 50.
Police are desperately hunting a "violent and armed" man after Monday's deadly truck attack on a Berlin Christmas market, in a bungled operation that has exposed major flaws in Germany's security system.
Police have confirmed they are searching for a Tunisian man, known as Anis Amri, whose immigration papers were found inside the vehicle that barrelled through the Christmas market in the heart of the German capital, leaving 12 dead and 48 injured.
The suspect was reportedly on the radar of authorities as far back as June, when they tried - and failed - to deport him after learning he was plotting a "serious act of violent subversion," according to a German security official, Associated Press reports.
As details continue to emerge of the suspect, the frenzied Europe-wide manhunt is increasingly proving a disaster for German security. Anis Amri is aged 23 and has used six aliases in the past, with passports and identity documents bearing different names and ages, according to police. Among these, he posed as Egyptian and Lebanese and frequently changed his place of residence.
Born in the city of Tataouine, in southern Tunisia, it is unclear when he came to Germany. His application for asylum was refused in June this year, but according to some reports he arrived in July 2015. Before that, he is believed to have been in Italy, possibly since as long ago as 2012.
The document found under the driver's seat of the lorry that ploughed into crowds of Germans and tourists is one given to asylum seekers in Germany, allowing them to legally remain in the country while their claim is decided.
Newspaper Sueddeutsche Zeitung reports the suspect had been in contact with the "network of a leading Islamist ideologist" known as Abu Walaa.
He has addresses both in Berlin and in the state of North Rhine Westphalia where he was registered.
A German security officials told AP authorities had previously considered Anis Amri "a possible terror threat". Security agencies exchanged information as recently as November that allegedly tied him to Islamist militants, but the 24-year-old was able to evade terror investigators.
This handout computer screen grab shows a copy of the arrest warrant over a Tunisian man identified as Anis Amri. Photo / AP
Prosecutors in Berlin told AP that they launched an investigation of the Tunisian man on March 14 after a tip-off from federal security agencies. The tip warned that he might be planning a break-in to finance the purchase of weapons for use in an attack.
Surveillance showed that Anis Amri was involved in drug dealing in a Berlin park and involved in a bar brawl, but the observation was called off in September when they found no evidence to substantiate the warning.
He was due to appear in court over the summer but failed to appear.
Describing him as "violent and armed", authorities have issued a European arrest warrant for Anis Amri, with a reward of up to 100,000 euros (NZ$150,950).
Germany issued a notice to other European countries overnight seeking his arrest, after initially holding off on going public so as not to jeopardise the manhunt.
Police in Berlin said they had received more than 500 tips on the attack as of Tuesday night, including 80 being followed up as leads as Germany continues to mourn the atrocity. Authorities did not say if they were looking for more than one suspect.
Police believe the suspect is injured, possibly badly, and are scouring German hospitals to try and find him. DNA traces from the driver found in the car have been secured.
Officials have said they are treating the incident as an act of terrorism.
German Interior Minister Thomas de Maiziere confirmed that authorities had identified a new suspect.
"There is a new suspect we are searching for - he is a suspect but not necessarily the assailant," he told reporters.
Rescue workers at the scenes and the truck that crashed into a Christmas market, in Berlin, Germany. Photo / EPA
Der Speigel reports that Anis Amri regularly changed his place of residence and his identity. In Berlin he was captured as Ahmad Z or Mohammed H from Egypt. On another occasion, he said he was from Lebanon.
The attack could prove to be political disaster for German Chancellor Angela Merkel, who will seek a historic fourth term next year.
Ms Merkel has staked much of her political capital on opening Germany's doors to refugees. She was named Time magazine's 2015 Person of the Year largely due to her acceptance of nearly a million mostly Muslim asylum seekers.
Ms Merkel, who has come under renewed pressure for her open-door migration policy, said she was "shocked, shaken and deeply saddened" by the attack. She told reporters it would be "particularly sickening" if the perpetrator was an asylum-seeker.
"We don't have anything for certain, but we must assume it was a terrorist attack," Ms Merkel said in a press conference.
"I know it would be especially hard for us all to bear if it were confirmed that the person who committed this act was someone who sought protection and asylum," she added.
Monday's Christmas market attack exposes the chaotic way German authorities have been struggling to cope with the influx of people with no clear system and no border control. Ms Merkel's opponents have seized on this over the past 48 hours and have rushed to lay blame on her pro-migrant government, demanding immediate changes.
On Tuesday, Dutch politician Geert Wilders tweeted a provocative, bloody image of Ms Merkel, blaming her for the carnage. The photoshopped image shows the German chancellor splattered with blood.
In a previous tweet, the anti-Islamic Freedom Party leader blamed "cowardly government leaders" for instituting "open borders" that had allowed a "tsunami" of Islamic terror to enter Europe.
Marcus Pretzell, chairman of the right-wing populist party Alternative for Germany (AfD) tweeted: "When will the German legal state strike back? When will this damned hypocrisy finally stop? These are Merkel's dead!"
AfD party leader Frauke Petry said Germany was no longer safe and "radical Islamic terrorism has struck in the heart of Germany".
The incident evoked memories of the horror in Nice back in July, when a Tunisian-born man carried out a similar attack on Bastille Day revellers in the southern French city, killing 86 people. That attack was claimed by Islamic State. The suspect was shot to death.
The German government has now agreed on a bill that will strengthen video surveillance.
The move has been planned for months but was approved by the cabinet on Wednesday as police continue to scramble for CCTV footage of Monday's deadly attack.
The proposed law would make data protection commissioners give greater weight than before to "the protection of life, health and freedom" when deciding whether to permit video surveillance in public places.
Germany has traditionally had very restrictive data protection rules. The bill needs to be approved by Parliament.
Investigators were also trawling through hundreds of photographs and videos taken by survivors at the Christmas market on their mobile phones.
German newspapers are reporting that the search for Anis Amri is focused on the North Rhine-Westphalia district near Cologne, southeast of the capital Berlin.
The wanted poster issued by German federal police shows 24-year-old Tunisian Anis Amri, suspected of being involved in the fatal attack on the Christmas market in Berlin. Photo / AP
Police on Tuesday released their former chief suspect, a 23-year-old Pakistani asylum seeker identified as Naved B, for lack of evidence. The man was originally arrested on suspicion of being the driver.
The Sun is reporting German police "botched" their hunt for the killer by arresting the wrong man and wasting valuable time.
On Wednesday, as police conceded they had given the real killer an 18-hour headstart, they admitted: "We cried hurrah too quickly."
The Polish driver behind the wheel of the lorry when it was hijacked, Lukasz Urban, was found beaten, shot and stabbed to death inside while the attacker fled the scene on foot.
There are reports emerging that Mr Urban may have been alive and potentially trying to stop the attack when he was shot.
Police and intelligence agencies are trying to work out whether the attack was carried out by a "lone wolf" single attacker, or if he was supported by others.
German Chancellor Angela Merkel lays flowers at the site where a truck crashed into a Christmas market in Berlin. Photo / AP
The head of the Association of German Criminal Detectives, Andre Schulz, told local media that police hoped to make another arrest soon.
"I am relatively confident that we will perhaps tomorrow or in the near future be able to present a new suspect," he said.
Six of those killed in the attack were German. Of the other five, one is believed to be an Italian woman. Twenty-four people injured in the attack remain in hospital, 14 in a critical condition.
Islamic State has claimed it was behind the attack. The group's news agency Amaq said one of its "soldiers" had carried out the deadly crash.
