German police are hunting for a Tunisian refugee in connection with the deadly truck attack at a Berlin Christmas market — identifying him after finding an asylum document under the vehicle’s driver’s seat, according to reports.

The asylum seeker, who was born in the southern Tunisian city of Tataouine in 1992, is named in the document as Anis Amri, German news site Spiegel Online reported.

A German security official told CNN that Amri had been arrested in the southern town of Friedrichshafen in August with forged documents en route to Italy but was released by a judge.

He is a “highly dangerous” member of a large Islamic group and received weapons training abroad before arriving in Germany last year, security sources told the Daily Mail.

Amri, who uses three different names, was arrested in August with a fake Italian passport and released — but his phone was said to be monitored, the Mail reported. He then disappeared in December.

The asylum document found in the truck announced a stay of deportation, the Telegraph of the UK reported. The document was issued in the town of Kleve near the border with the Netherlands and Belgium.

A Facebook profile in his name shows “likes” of Tunisian terror group Ansar al-Sharia, whose jihadists slaughtered 22 people at Tunis’ Bardo Museum in March 2015 and then 39 tourists at a beach resort in Sousse.

Amri, who may be injured, was being sought in the western state of North Rhine-Westphalia, where he had been registered at a refugee shelter in the town of Emmerich on the Rhine, on the Dutch-German border, The Guardian reported.

He had ties to Salafism — an ultra-conservative branch of Sunni Islam — in connection with Islamist hate preacher Ahmad Abdelazziz A, known as Abu Walaa, from Hildesheim in Germany, the Sueddeutsche Zeitung newspaper reported. Abdelazziz was arrested in November.

Police on Tuesday released their former chief suspect, a 23-year-old Pakistani asylum seeker identified as Naved B, for lack of evidence.

German Interior Minister Thomas de Maizière confirmed Wednesday that a new suspect was being sought, but said he could not confirm his identity.

“It is important that we find this suspect, and that’s why it is important to carry out an undercover search,” he said. “We are gathering the data and all the evidence.”

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, Reuters reported.

State broadcaster ARD and Sueddeutsche Zeitung reported that Amri arrived in Italy in 2012, then moved to Germany in July 2015 and applied for asylum, The Guardian reported.

Since April, his status has been listed as “temporary suspension of deportation” — meaning his application was rejected but he had not yet been forced out of the country.

But another report emerged in the newspaper Der Spiegel, which cited intelligence sources saying Amri was detained to be deported in Ravensburg on July 30, but his whereabouts after that were unclear.

Twelve people were killed and 48 injured in what German authorities have called a “terrorist attack” late Monday when the truck — belonging to a Polish freight company — plowed into a crowd of shoppers.

The Polish driver of the truck, who was found shot dead in the cabin, was alive until the attack took place, Bild reported. An investigator said there must have been a struggle with the attacker.

The ISIS-linked Amaq news agency said “a soldier of the Islamic State” carried out the carnage “in response to appeals to target citizens of coalition countries.”

The site offered no evidence to back the claim and did not identify the attacker.

ISIS also claimed responsibility for a similar attack on July 14, when a Tunisian-born man drove a truck through a crowd celebrating Bastille Day in the French city of Nice. Eighty-six people were killed, and the driver was shot dead by police.

Tunisia is one of the biggest suppliers of jihadist fighters — with about 5,500 of its nationals believed to be involved in combat in Syria, Iraq and Libya, AFP reported.

Meanwhile, Passauer Neue Presse quoted Klaus Bouillon, the head of the group of interior ministers from Germany’s 16 federal states, as saying tougher security measures must be implemented.

“We want to raise the police presence and strengthen the protection of Christmas markets. We will have more patrols,” he said. “Officers will have machine guns. We want to make access to markets more difficult, with vehicles parked across them.”

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German Chancellor Angela Merkel has said it would be particularly repugnant if an asylum seeker seeking protection in Germany was the perpetrator.

Some politicians have blamed her open-door migrant policy for making such attacks more likely.

The anti-immigrant Alternative for Germany, which has won support in the last two years as Merkel’s own popularity has declined, said Germany is no longer safe.

Some politicians have called for changes to Merkel’s immigration and security policies after she allowed more than a million refugees to enter the country in the last two years — many fleeing countries such as Syria, Iraq and Afghanistan.

Bavarian Interior Minister Joachim Herrmann told German radio on Wednesday that there was a higher risk of Islamist attacks because of the influx of refugees.

In other developments, German President Joachim Gauck visited some of the wounded at a Berlin hospital, where they are being treated for pelvic and other injuries.

Gauck said he spoke with three patients at the Charite hospital who faced operations on Wednesday and he was impressed by their “composure.”

He also met a man who had rushed to help in the aftermath of the rampage and was hit by a steel beam.

The Charite took in 13 patients after the attack, two of whom died. Medical director Ulrich Frei said that four have “severe trauma of the lower extremities and the pelvis.”

One of those wounded in the attack was an Israeli man whose wife is missing, the Israeli Foreign Ministry said.

Ministry spokesman Emmanuel Nahshon said Wednesday that the man is in stable condition after surgery. Israel is in touch with German authorities to try to find the wife.

He declined to disclose the couple’s personal details, saying only that they were in Berlin on holiday and that their relatives had arrived in Germany on Tuesday.

With Post wires