By Paul Davies: ITV News Correspondent

This week of all weeks it is deeply troubling to see heavily-armed soldiers outside synagogues and other Jewish cultural centres in Europe's major cities.

There are still survivors of the Holocaust who remember all too clearly the uniformed men who rounded up their families and friends before herding them to the extermination camps.

True, the paratroopers posted outside the Jewish places of worship and schools in Brussels and Antwerp today are there to protect the Jewish population from terrorist attack.

But their presence reflects an official acceptance that there is a new threat and a new wave of antisemitism that sits uncomfortably alongside the ceremonies to remember the liberation of the Auschwitz death camp 70 years ago.

In one Brussels synagogue we met Rabbi Menachem Margolin who said fear had returned to the Jewish community. Many families were planning to emigrate to Israel, Canada or Australia.

The soldiers at the door were not enough, he said. He wanted changes in the law to allow Jews to carry guns at synagogues, schools and other potential targets.

Antisemitism takes many forms in today's Belgium. At it's deadliest a gunman opened fire on visitors inside Brussels' Jewish Museum last summer, killing four people.

The garden housing the memorial to 25,000 Belgian Jews who disappeared in the Nazi death camps has to be locked because of repeated acts of vandalism.

In Antwerp we met 90-year-old Bertha Klein, who says antisemitism has always existed but is being expressed more openly today than it has been for many years.

Bertha was a teenager when she survived the Holocaust by hiding in a forest with other Jewish fugitives. Her mother was shot by the Nazis while trying to escape.

Now a frail grandmother with heart problems, Bertha recently experienced the modern version of antisemitism when she suffered a fall and broke a rib.

The medic who took her emergency call would not come out to treat her when he heard her Jewish name.

Bertha Klein was a teenager when she survived the Holocaust. Credit: ITV News

"When I said I was in pain he said I should go to Gaza to find out what real pain is."

Bertha's family are campaigning for an inquiry into the doctors response.To date the police have taken no action.

They do however report 200 antisemitic incidents in Belgium last year, a worrying 60 per cent increase on 2013.

"Antisemitism exists, it never died," says Bertha sadly. "I am afraid the spirit of Hitler lives on in some people."