Angela Merkel’s own deputy has branded a growing catalogue of German security blunders “shocking” as the suspected Berlin attacker remains on the run.

Fingerprint evidence places Anis Amri behind the wheel of a hijacked lorry used to massacre 12 people at one of the German capital’s most popular Christmas markets in a terror attack claimed by Isis.

Authorities have admitted letting the 24-year-old Tunisian slip through the net after he was investigated over a previous terror plot and put under surveillance for six months, but not arrested.

Who is the prime suspect in the Berlin Christmas market attack?

An attempt to deport Amri after his asylum application was rejected failed in June because Tunisia had no proof of his nationality.

Armin Laschet, the deputy chairman of Ms Merkel’s Christian Democratic Union (CDU) party, said the revelations must have consequences for the German government.

“The information we have been receiving can only leave one shocked about how the authorities have worked,” he told Deutschlandfunk radio.

“The first phase is to first find the culprit... and then I think a political, parliamentary and administrative appraisal must take place to see what consequences can be drawn.”

The anti-immigration Alternative fur Deutschland (AfD) party is among those seeking to capitalise on the attack ahead of next year’s elections, when Ms Merkel will be running for a fourth term as German Chancellor, and the atrocity has sparked protests by left and right-wing groups.

Critics have blamed her decision to open Germany’s borders during the height of the refugee crisis for the massacre and two previous terror attacks carried out by asylum seekers pledging allegiance to Isis.

Berlin Christmas market lorry attack Show all 18 1 /18 Berlin Christmas market lorry attack Berlin Christmas market lorry attack Several people have been killed after a lorry drove into crowds at a Christmas market in Berlin REUTERS/Fabrizio Bensch Berlin Christmas market lorry attack 'At least nine' people have been killed and more than 50 injured. AP Berlin Christmas market lorry attack Emergency Services rush a Berlin market victim to an ambulance Associated Press Berlin Christmas market lorry attack Police cordoned off the square at Kaiser Wilhelm Memorial Church following the incident REUTERS Berlin Christmas market lorry attack Rescue workers inspect the lorry that crashed into a Christmas market close to the Kaiser Wilhelm memorial church in Berlin EPA Berlin Christmas market lorry attack Emergency crews inspect the lorry that ploughed into a Berlin Christmas market, killing at least nine people AFP Berlin Christmas market lorry attack Fire crews attend the scene of the attack AFP/Getty Berlin Christmas market lorry attack Armed police secure the site of a lorry attack at a Christmas market in Berlin REUTERS Berlin Christmas market lorry attack Crushed debris is visible beneath the wheels of the vehicle REUTERS Berlin Christmas market lorry attack An injured man is pushed to an ambulance REUTERS Berlin Christmas market lorry attack Medics attend an injured person after the lorry attack which killed at least nine and injured more than 50 people AFP/Getty Berlin Christmas market lorry attack Firefighters examine the lorry which was rammed into a Berlin Christmas market REUTERS Berlin Christmas market lorry attack A person is carried into an ambulance REUTERS Berlin Christmas market lorry attack View of the lorry that crashed into a Christmas market in Berlin, killing at least nine and injuring at least 50 people AFP/Getty Berlin Christmas market lorry attack Rescue workers push a person on a stretcher to an ambulance Getty Berlin Christmas market lorry attack Firefighters assess the damage after the lorry rammed the Christmas market, killing 'at least nine', and injuring more than 50 people AP Berlin Christmas market lorry attack Firefighters stand beside a toppled Christmas tree at the site of the suspected terrorist attack in a Berlin Christmas market AP Berlin Christmas market lorry attack Damaged stalls at the scene of the incident at a Berlin Christmas market where at least nine people have been killed EPA

Ms Merkel told a press conference she was hoping for Amri to be arrested quickly as a Europe-wide manhunt continued.

“I am certain we will meet this test we are facing,” she said. “In the past few days I have been very proud of how calmly most people reacted to the situation.”

She hailed the “highly professional work” of police and “smooth cooperation” with international partner organisations.

As well as being in contact with known Islamist preachers, Amri is reported to have offered himself as a suicide bomber on extremist chat sites. The messages were uncovered in a separate counter-terror probe but the wording was not deemed conclusive enough to warrant an arrest, Der Spiegel reported.

He also raised a red flag for counter-terror agencies in the US, which put Amri on a no-fly list after finding he had conducted online research into making improvised explosive devices and communicated with Isis militants on the Telegram messaging app.

Earlier this year, he spoke to two Isis fighters and Tunisian authorities listened in on their conversation before informing German authorities, Bild said.

Prosecutors launched a previous probe into claims Amri was planning a break-in to finance buying automatic weapons for an attack, but surveillance that started in March failed to reveal evidence of a terror plot and was stopped in September.

Anis Amri, the Berlin attack suspect (Facebook)

Stephan Mayer, a politician from the Christian Social Union party, said the new suspect had ties to a network of Islamic extremists, reported to include a hate preacher known as Abu Walaa, who was arrested as part of a cell of Isis supporters sending militants to Syria earlier this year.

Amri was also said to have followed an extremist preacher known as Boban S, who was arrested in Dortmund on suspicion of supporting Isis in November.

Dortmund was one site of a series of raids linked to the case today. Federal prosecutors did not give details of the operations in North Rhine-Westphalia and Berlin but several of Amri’s suspected associates were said to have been arrested.

A mosque was stormed in the German capital, with local reports saying armed police used stun grenades and blew up a door to access the building, where worshippers were investigated for allegedly supporting Isis earlier this year.

Officers also stopped a coach travelling through Heilbronn, in Baden-Württemberg, but there was no sign of Amri.

Federal prosecutors confirmed he was believed to be the driver of the lorry used to attack the Christmas market after his fingerprints were found on the door and inside the cab, where asylum documents revealing Amri’s identity were previously discovered.

“It is highly probable that the suspect is, in reality, the perpetrator,” interior minister Thomas de Maizière told reporters.

Amri’s family urged him to turn himself into police, voicing shock over his suspected crime.

The attack in Berlin killed 12 people (Hannibal Hanschke/Reuters)

His mother, Nour al-Houda Hassani said poverty drove him into crime and later to travel to Europe by boat during the 2011 Arab Spring.

“I want the truth to be revealed about my son,” she said. “If he is the perpetrator of the attack, let him assume his responsibilities and I’ll renounce him before God. If he didn’t do anything, I want my son’s rights to be restored.”

Amri’s brothers said they had not heard from him since Monday’s attack, telling the Associated Press he may have been radicalised while serving a three-and-a-half year prison sentence for setting fire to a refugee centre in Italy.

The Italian justice ministry described Amri as a problematic inmate, saying he was transferred between six different prisons in Sicily for bad conduct including bullying and trying to spark insurrections, although no sign of radicalisation was detected.

Amri’s estranged father told a Tunisian radio station his son had a lengthy criminal past, being sentenced in absentia to five years in prison for aggravated robbery in his hometown of Oueslatia.

Isis has gained a foothold in Tunisia, launching several attacks, and is known to target young criminals with propaganda offering redemption through jihad.

A European arrest warrant issued for Amri lists six different aliases, going under different names, birth dates and even nationalities.

The technique has previously been used by Isis militants including the Paris and Brussels attackers in attempts to throw authorities off their scent.

People take part in a vigil in Berlin, Germany after the truck attack at the Christmas market (Lizzie Dearden)

Prosecutors are offering a €100,000 (£85,000) reward for information leading to Amri’s arrest, warning people not to approach the “violent and armed” suspect.

There were fears the attacker could pose a further danger to Germany after killing 12 people and injuring at least 56 more.

Berlin’s state government said some of the 12 people still being treated for severe injuries remained in a critical condition, with 14 others in hospital for less serious wounds and 30 discharged.

In a show of defiance, crowds poured back into the partly destroyed Christmas market as it reopened, leaving flowers and candles at makeshift memorials bearing handmade signs calling for peace and unity.

Germans and tourists returned to the festive stalls surrounding the Kaiser Wilhelm Memorial Church inside a ring of concrete defences and under the watchful eye of squads of armed police.

The attack has sparked increased security at churches and Christmas events around Europe, including in London.