Anis Amri, the main suspect in the Berlin Christmas market truck attack, has been killed in a shootout in a suburb of the northern Italian city of Milan, Italian authorities said.

Interior minister Marco Minniti told a news conference on Friday in Rome that Amri had been fatally shot after firing at police who had stopped his car for a routine identity check around 3am (02:00 GMT).

Identity checks had established "without a shadow of doubt" that the dead man was Amri, the minister said.

The shootout took place in Milan's Sesto San Giovanni neighbourhood.

Minniti added that the suspect, a 24-year-old Tunisian, pulled out a gun from his backpack after being asked to show his identity papers. A police officer was injured in the shootout.

The minister gave very few details of the police operation, saying investigations were still in progress.

He added that there could be "future developments".

A Europe-wide search for Amri was launched and he was described by authorities as 'violent and armed' [Reuters]

ISIL has claimed responsibility for Monday's attack, in which the truck drove through a crowd of people and bulldozed wooden huts selling Christmas gifts and snacks beside a famous church in west Berlin.

ISIL on Friday said in a statement on its Amaq website that the "Berlin attacker ... was killed in an exchange of gunfire".

The group also released a two-minute video showing Amri pledging allegiance to ISIL in a video, as he called for attacks against "Crusaders".

Germany's Chancellor Angela Merkel thanked Italian authorities, expressing relief that the suspect posed no further threat.

"We have also made progress this year on the very important issue of deporting Tunisian citizens who have no right to stay in Germany," Merkel said. "I told the Tunisian president [Beji Caid Essebsi during a phone call] that we have to significantly speed up the deportation process and increase the number of people sent back."

One of the 12 killed in Berlin was the Polish driver from whom the lorry had been hijacked. His body, stabbed and shot, was found in the cab.

Germany had launched a Europe-wide manhunt for Amri, who was described as "violent and armed".

But it emerged that he was already under investigation.

The interior minister of Germany's North Rhine-Westphalia (NRW) state, Ralf Jaeger, said counterterrorism officials had exchanged information about Amri, most recently in November, and a probe had been launched suspecting he was preparing "a serious act of violence against the state".

Berlin prosecutors said Amri had been suspected of planning a burglary to raise cash to buy automatic weapons, "possibly to carry out an attack".

Amri's brother seeks 'the truth'

The Tunisian hometown of Berlin attack suspect Anis Amri is reeling at news that he was killed by police in Milan.

Amri's brother Abdelkader told The Associated Press by telephone Friday that the family wants to find out the "truth about my brother." He hung up when asked about the family's reaction to Amri's death.

The family ordered a crowd outside their house to leave when news of Friday's police shootout reached the central Tunisian town of Oueslatia, according to neighbor Wiem Khemili.

Police stood guard around the impoverished town, where everyone is talking about Amri.

WATCH: Why is Germany being targeted?

Amri's mother and siblings have questioned German authorities' accusation that Amri was the attacker.

Al Jazeera's Dominic Kane, reporting from Berlin, said that German newspapers' headlines on Friday morning threw "accusations of ineptitude" at authorities over the attack.

"Let's remember there's a general election coming up in Germany in the not to distant future," he said. "Many questions are going to ensue for the government here about what they knew about this individual, prior to the attack on Monday night."

Kane added: "There are also questions over how this individual could have travelled from the capital in the northeast of Germany 1,000 kilometres across Europe, as one of the most wanted men in Europe, to Milan."

Source: Al Jazeera and news agencies