The German government failed relatives of the victims of last year's devastating Christmas market attack in Berlin, the country's president has admitted.

Speaking on the anniversary of the attack, President Frank-Walter Steinmeier told survivors and families that the government had not provided adequate support and comfort.

It is a year to the day since rejected Tunisian asylum seeker Anis Amri rammed a truck into the crowded market at Breitscheidplatz, killing 12 and wounding 70 others.

Criticised: German Chancellor Angela Merkel holds a candle at the memorial event today, marking the first anniversary of the terrorist attack on Christmas market in Berlin

In memoriam: It is a year to the day since rejected Tunisian asylum seeker Anis Amri rammed a truck into the crowded market at Breitscheidplatz, killing 12 and wounding 70 others

Apologetic: German President Frank-Walter Steinmeier, second from left, told survivors and victim's families that the government had failed in providing support

Chancellor Angela Merkel, who unveiled a memorial honouring the victims today, has come under fire over security failings and the government's clumsy handling of the aftermath of the assault.

'It is true that some support came late and remained unsatisfactory,' President Frank-Walter Steinmeier told the bereaved and emergency workers at a private church memorial for the victims.

'Many family members and injured - many of you - felt abandoned by the state,' he said, recalling the words of a mother who had lost her daughter and said no-one had comforted her after the attack.

'I can't get those words out of my head,' he admitted, saying that the relatives' appeal to be heard had 'triggered something and set it in motion.'

In the hours following the assault, politicians had put on a brave front and repeated the mantra that Germany would not be cowed by terror.

Dozens of people had gathered by the new memorial on the anniversary of the attack

German Chancellor Angela Merkel made a speech during the opening of the memorial site

Heartbreaking: Pictures of victims are placed at the memorial for the victims of the Christmas market attack in front of Kaiser-Wilhelm-Gedaechtniskirche prior to the commemorative events marking the first anniversary of the terrorist attack

Mourners lay flowers and candles following the inauguration the memorial to victims at the site of the 2016 Christmas market terror attack at Breitscheidplatz

Not good enough: Merkel, who unveiled the memorial today, has come under fire over security failings and the government's clumsy handling of the aftermath of the assault

Chancellor Merkel, who attended several events today, only met victims' families and survivors on Monday, German media reports

But Steinmeier acknowledged such rhetoric had done little for the victims.

'So soon after the attack ... these words don't sound simply defiant and self-confident, but also strangely cold and detached,' he said.

To mark the anniversary, the popular Christmas market at Breitscheidplatz will stay shut all day out of respect for the victims.

Mrs Merkel unveiled the memorial, a 46-foot golden crack in the ground with the steps above engraved with the victims' names at midday today.

The Chancellor remained solemn as she stood by the memorial which had been decorated with white roses.

But the run-up to the commemoration has been marred by criticism of the authorities by families of the victims.

A wrenching open letter by some of the bereaved accused Merkel of failing to personally offer condolences.

The chancellor held her first meeting with relatives only on Monday.

Acknowledging the criticism, Merkel said: 'It is clear to me that their suffering, this complete transformation of their lives, cannot be put right.

'But nevertheless we can show compassion and will improve the things that must be improved.'

Under attack: Many survivors and families of those who were killed in the attack have expressed anger towards Merkel and her government

This year's Christmas market can be seen in the background of the memorial

Honoured: The memorial is a 46-foot golden crack in the ground with the steps above engraved with the victims' names

In an editorial in Tagesspiegel daily, Justice Minister Heiko Maas apologised.

'We were not sufficiently prepared to deal with the consequences of such a terror attack,' he wrote.

'For that, we can only apologise to the victims and their surviving relatives.'

Kurt Beck, who was commissioned by the government to look into the handling of the aftermath, last week outlined a litany of official failings, including taking up to three days to inform anxious relatives that their loved ones had perished and even sending the bereaved autopsy bills complete with late payment warnings.

Further adding to the embarrassment, Bild daily said the letter inviting relatives to Tuesday's commemoration was accompanied by an information sheet stating that 'taxi costs will not be reimbursed!' and urging them to use public transport instead.

A spokeswoman for Berlin authorities, Claudia Suender, told Tagesspiegel that such information was 'required under budgetary and administrative law' even if she 'regretted the impression it gave.'

Police also faced fierce criticism after it emerged that Amri, who arrived in Germany in 2015 and registered under several different identities, should have been deported.

On Sunday, Welt am Sonntag newspaper said the Tunisian had been under closer surveillance by Germany's secret service than previously thought, suggesting the authorities may have left him free in order to detect his instigators.

Amri himself was shot and killed four days after the attack by police in Italy, where he had previously lived.

Tonight at 8:02 pm (7.02pm GMT) - the exact time when Amri rammed his truck into the crowded square a year ago - there will be a public ecumenical prayer when people can light candles and the church's bells will chime for 12 minutes.