A defiant chancellor Angela Merkel has conceded Germany is “at war” with Islamist terrorist groups, but insisted they would neither undermine German values nor force a change to her refugee strategy.

Amid growing unease after a bloody 10 days in Germany - with axe, machete and bomb attacks carried out by refugees and asylum seekers, and a mass shooting by a German teenager - Dr Merkel shrugged off growing domestic pressure and insisted her priority is to restore public trust and minimise angst.

The German leader interrupted her holiday for press conference in Berlin, batting off suggestions it was time for her to stand down and insisting she would correct elements of her refugee strategy rather than allow it - or her - be sidelined.

“I stand by the main decisions we made,” she said. “We have achieved a lot even though in these days it is clear what we have yet to do.”

Almost exactly a year ago, the German leader insisted her country was strong enough to manage the looming challenge posed by a migration crisis of historical proportions, one that attracted over one million people to Germany last year.

Today she said opening Germany’s borders last September to 10,000 Syrian refugees trapped in Hungary remained the only correct humanitarian response.

Islamist groups had exploited this opportunity to smuggle terrorists into Europe and Germany, she conceded, “mocking the country” that helped refugees.

The recent attacks came amid an already cooling welcome in Germany for refugees, following New Year’s Eve sexual assaults by non-nationals on women.

But the challenge was to face down those who terror campaign had sparked the refugee crisis, she said, not to crack down on those fleeing the resulting terror. Her year-old mantra - “we can manage this” - still applies, she said.

”Today as then I am convinced that we will manage our historical challenge,” she said. “Given the new challenges we face - shaped by Islamist terror - we will introduce the correct measures and make clear we want to give our citizens security and master the integration challenges”.

‘Security through strength’

Amid pressure from her political allies in Bavaria - on the front lines of the refugee crisis and the recent terror wave - Dr Merkel presented a nine-point “security through strength” plan to improve the fight against terrorist acts and structures.

Among the measures: a new body to decrypt internet communication; additional security staff; a national migration register; and an early warning system to catch radicalised refugees.

While other European neighbours have increased their terror warning, Dr Merkel said now was the time for cool heads and retooling existing security and integration measures.

”That we are in a struggle and war against Isis is uncontested, we are not in a war against Islam but against ... Islamist terrorism,” she said.

Again and again she refused to admit any failures in the last year but, with an eye on damage limitation, Dr Merkel pointed out that all decisions she took were made in consensus with other political players, police and security services.

Her Bavarian allies, the Christian Social Union, pushed ahead with their own post-attack plan on Thursday, promising tighter security measures and expedited deportations of failed asylum seekers, such as the Syrian man behind Sunday night’s bomb attack.

CSU leader Horst Seehofer, a vocal critic of last year’s open-door border policy, hit out at the German leader saying: “All our predictions have been proven right ... Islamist terrorism has arrived in Germany.”

Amid growing criticism of Berlin’s refugee open door on Germany’s political fringes - left and right - Dr Merkel did little more than take note of Bavaria’s anti-terror proposals while warning Germans not to follow populists “with hate in their hearts”.

The large number of refugees in the country was, she said, “no excuse for xenophobia” and she vowed to win back people who had drifted to the extremist fringes in anger at her refugee policies.

Asked why she had not travelled to any of the towns and cities struck by violence in the last 10 days, a move that has attracted criticism in some quarters, Dr Merkel said she had decided to attend a state mourning ceremony at the weekend in Munich.

It was just one of several defensive answers in a press conference which offered a series of pointed questions about her recent political performance, her legacy and her future.

Heading into the last year of her third term, after 11 years in power coloured by more crises than many of her predecessors combined, Dr Merkel refused to take the bait when asked if it had all left her exhausted.

A year before the next federal election, the German leader was anxious to show no signs of flagging.

“The role of the state is to restore trust, that is what we are working on,” she said. “But there are reasons when I’m glad to go to bed.”