Berlin: The suspect in the Berlin Christmas market attack was shot dead on Friday at a Milan checkpoint by an Italian police trainee, bringing an end to an international manhunt for the 24-year-old Tunisian that had kept the continent on edge as the holidays approached.

Anis Amri was killed following a dramatic encounter in the Piazza I Maggio in the Sesto San Giovanni area outside Milan, after a two-man patrol stopped him for questioning after 3am on suspicion of burglary. One of the officers requested his identification. Amri responded by pulling a gun and shooting one officer in the shoulder.

The second patrolmen, trainee Luca Scata, 29, fired back, killing Amri, according to Italian officials.

There has been a four-day Europe-wide manhunt for Amri, a 24-year-old Tunisian national who is believed to have driven a large truck laden with steel into a Berlin Christmas market late Monday, killing 12 people and injuring 48, 

"He was the most-wanted man in Europe," said Italian Interior Minister Marco Minniti.

"There is absolutely no doubt that the person killed is Anis Amri."

In Germany, Federal Attorney General Peter Frank said fingerprints confirmed Amri was the man killed.

Hours after the shootout, the Islamic State-linked news agency, Amaq, released a video that purports to show Amri swearing allegiance to Abu Bakr al-Baghdadi, the self-proclaimed caliph of the Islamic State.

Speaking in black-hooded windbreaker on an iron bridge with white railing and scrawled graffiti, he called on Muslims in Europe to rise up and strike at "crusaders."

"God willing, we will slaughter you like pigs," he said in the video, whose date and location was not given.

He added, "to my brothers everywhere, fight for the sake of Allah. Protect our religion. Everyone can do this in their own way. People who can fight should fight, even in Europe."

The authenticity of the video could not be independently confirmed, but previous material released by Amaq has been credible.

Earlier, a statement carried on Amaq described Amri as inspired by the Islamic State.

In Italy, Minniti said he had phoned the wounded Italian officer, Cristian Movio, and Scata, an agent-in-training. Already, Facebook sites and other social media sites were popping up, including ""give Luca Scata a medal" and "Luca Scata world HERO."

"Thanks to him Italians can have a Merry Christmas," Minniti said.

Italian Prime Minister Paolo Gentiloni told reporters that he called German Chancellor Angela Merkel to relay the news.

A German security official briefed on the case said that the Italians had identified Amri via a confirmed fingerprint match.

While Amri's death ended an international manhunt for the suspect who it also raised a whole new set of questions.

Amri appeared to travel right under the noses of European authorities, though via a circuitous route, raising questions about how he managed to evade European dragnets for at least two days after authorities had identified him as the prime suspect.

After leaving Berlin, Amri is believed to have traveled by train through the French city of Chambery, and appears to have stopped in Turin, Italy, before arriving in Milan, said Alberto Nobili, Coordinator of the Anti-Terrorism department at the District Attorney's office in Milan.

Frank, the German prosecutor, said the investigation "continues with high intensity."

The main aim was to find out which route Amri had taken from Berlin and whether he had any supporters. "These are questions one surely has to ask," he noted.

Nobili said Italian authorities were sharing ballistic information with the Germans to ascertain whether the gun used to shoot the Italian police officer was the same as the one used to slay the Polish driver whose truck Amri is believed to have hijacked on Monday before slamming into the Christmas market.

His death in Italy also raised serious questions about the handling of the case by German authorities. German investigators only uncovered their single biggest clue - his wallet with identification left in the truck's cabin - the following day after the attack, suggesting the delay may have facilitated his flight from Germany.

"We need to increase international collaboration against terrorism," Gentiloni said.

Amaq, the news agency of the Islamic State - which had claimed it inspired Amri - confirmed his death. "The executor of the Berlin attack," it said, was "killed during an exchange of gunfire" with Italian police. Amaq described the wounding of the Italian policeman as Amri's final "attack."

By heading to Italy, Amri was, to some extent, retracing his steps. He had first arrived in Europe in April 2011 on the Italian island of Lampedusa, and spent four years in jail in Sicily, where Italian officials believe he was radicalized.

The news came as German police said they had thwarted yet another terrorist attack planned against a shopping mall and arrested two brothers from Kosovo.

Authorities detained the brothers, aged 28 and 31, after receiving an intelligence tip-off, according to North Rhine Westphalia police. Security at the Centro Mall in the western German city of Oberhausen has been beefed up.

Amri had a criminal record in Europe and his native Tunisia. Sought in his native Tunisia for hijacking a van with a gang of thieves, the Italians jailed him in 2011 for arson and violent assault at his migrant reception center for minors on the isle of Sicily.

There, his family noted, the boy who once drank alcohol - and never went to mosque - suddenly got religion.

He began to pray, asking his family to send him religious books. The Italian Bureau of Prisons submitted a report to a government anti-terrorism commission on Amri's rapid radicalization, warning that he was embracing dangerous ideas of Islamist extremism and had threatened Christian inmates, according to an Italian government official with knowledge of the situation. The dossier was first reported by ANSA, the state-run Italian news service.

The Italians tried to deport Amri but couldn't. They sent his fingerprints and photo to the Tunisian consulate, but the authorities there refused to recognize Amri as a citizen. The Italians, officials there say, could not even establish his true identity. Italy's solution: After four years in jail, they released him anyway - giving him seven days to leave the country.

He had previously known links to Islamist extremists, and German efforts to deport him also failed because Tunisia had initially refused to take him back.

The night before the attack, Amri called his family in Tunisia, as he would nearly every weekend. His birthday - on Thursday - was fast approaching, and he seemed animated.

"What's the weather like? Is it raining? What are you having for dinner?" his sister, Sayida Amri, 36, in his bleak home town of Oueslatia, Tunisia, recalled him asking Sunday. He asked her, she said, to pass the phone to his youngest niece, Zeinab - 4 years old.

"Do you even know who I am?" he asked her.

His case suggests two critical realities of modern terrorism that present major new challenges, especially in Europe. The cumbersome, sometimes flawed system of deportation and asylum - mixed with open borders - has made it exceedingly easy for radicalized Islamists to operate on the continent.

Yet Amri is also the latest suspect to have emerged from a disconcerting counter terrorism gap in both Europe and the United States.

In case after case - including that of the German Christmas market attack - authorities have come forward after the fact to say that they had enough cause to place the suspect under surveillance well before the violence. But never enough to move in for an arrest.

This has been true of the majority of lone-wolf terrorism plots over the past several years. The Orlando shooter, Omar Mateen, had been under FBI investigation for 10 months.

The bureau had also tracked but had been unable to build a case against the Boston Marathon bombers or the plotters who targeted a contest to draw cartoons of the prophet Muhammad.

The same was true with Amri.

Several months ago, during a surveillance operation monitoring radical Islamic preachers, German authorities intercepted a communication, which, in retrospect, appeared to forecast Amri's violent intent. They would not disclose the precise wording, but two German officials with knowledge of the investigation said the intercept was not straightforward enough to directly indicate an imminent threat.

"He never made such a clear statement during this interaction, which could have led to the conclusion that he would become a martyr," one of the officials said.

Amri fell into a dangerous gray zone - he was on the US no-fly list a month ago, and Germans had linked him to a radical network led by Abu Walaa, a 32-year-old of Iraqi descent arrested in November on charges of recruiting and sending fighters from Germany to the Islamic State.

Amri had also been under police surveillance for several months until September of this year, because he was suspected of planning a burglary in Berlin to finance the purchase of weapons. The suspicion wasn't confirmed, however, and authorities found him guilty only of being a small-time drug dealer.

"This kind of super-low-tech, improvised thing is hard," said Rafael Bossong, research associate at the German Institute for International and Security Affairs. "The guy didn't buy any weapons. He didn't give off absolutely clear signals. The question is, how do you definitely prevent that?"

Amri appears to have attempted to manipulate the German asylum system - an inundated bureaucracy clogged with a backlog of more than 400,000 cases following the arrival of 1.2 million asylum seekers over the course of the past two years.

According to Der Spiegel, he claimed to be Egyptian and to have suffered persecution there when applying for asylum in Germany in April. When officials questioned him, he could not answer basic questions about his alleged home country. They checked their data system and found that he had been registered under several aliases and birthdays. By July, his asylum request was rejected.

And yet, they could not deport him, because Tunisia initially refused to take him - issuing him a passport only last Monday, the same day as the attack.

Amri reportedly spent several years in Italy before entering Germany in July 2015.

The Washington Post