Since Donald Trump made his Jerusalem announcement this month, a series of antisemitic attacks and other incidents have taken place in Europe. They have drawn condemnation from political leaders and received some, but not much, media attention. These events are a sign that antisemitism in Europe could be getting worse.

The Holocaust is a defining legacy of European history. Europeans have a special responsibility to ensure Jews feel safe and free in our societies. There can be no justification for antisemitism. That may be stating the obvious, but these days it seems that the obvious needs to be stated.

On 9 December in Gothenburg, Sweden’s second largest city, a group of masked men attempted to set fire to a synagogue. They threw molotov cocktails, forcing young people who had been holding a Hanukkah party to seek refuge in the basement. Days later, a second arson attack occurred at a Jewish cemetery in Malmö, where there were also reports of calls for an “intifada” and violent, antisemitic shouts at a demonstration. In Amsterdam, a man holding a Palestinian flag smashed the windows of a kosher restaurant. The incident, recorded on video, was described by the Organisation of Jewish Communities in the Netherlands as “no less than an act of terror”.

Far-right antisemitism is part of our history. Today it lurks among Europe’s resurgent, nativist political movements

In Gothenburg, three men were detained for “attempted criminal arson” after the synagogue attack. According to the antiracist activist magazine Expo, they were two Syrians and one Palestinian. All three had arrived in Sweden this year. The Swedish prime minister Stefan Löfven declared there was “no place for antisemitism in our society”, while Angela Merkel commented that “no difference of opinion, including on the status of Jerusalem, can justify such acts”.

Antisemitism has mutated in Europe. Different strains of it have now developed. The far-right antisemitism that led to the Holocaust is part of our history. Today it still lurks among Europe’s resurgent, nativist political movements, including in the UK.

Muslims, too, have also bought into antisemitism. In 2013 Mehdi Hassan described the antisemitism among some British Muslims as “our dirty little secret”. Yet another form of antisemitism has hidden since the 1960s behind radical leftwing anti-Zionism and criticism of Israel.

People inspect the damage to a clothing shop window smashed by antisemitic gangs in east London in 1936. Photograph: Fox Photos/Getty Images

Neither Europe’s Muslims nor its radical left should be tarnished with antisemitism en masse, of course. Large majorities reject it. But if European democracy is to be protected, antisemitism needs to be exposed and combated much more actively. In my country, France, it took an attack on a kosher supermarket in Paris in 2015 for the scale and depth of antisemitic feeling among certain groups of radicalised youths to be grasped. The 2012 attack on a Jewish school in Toulouse – in which Mohammed Merah murdered three children, their teacher and others – had not been seen as the watershed it truly was.

I was visiting Sweden when the recent attacks unfolded, and was struck that there was no spontaneous public show of solidarity with the Jewish community. Sure, widespread indignation and concern were present – but somewhat discreetly.

Europe is not antisemitic. But we need to acknowledge that new versions of anti-Jewish sentiment exist. In Hungary, rabid antisemitic campaigns have flourished against George Soros, including posters harking back to an era we may have thought was long gone. But I’m told that some in the Hungarian Jewish community have become as worried about radical Islamist ideas as they are about extreme rightwing antisemitism, and are reluctant to call out the right as antisemitic for this reason. None of this is simple.

There is a growing awareness of the problem at EU level. The European parliament passed its first resolution on “combating antisemitism” in June. The text refers to a “working definition” which points out that antisemitism must not be seen as limited to the targeting of Jews. It can target non-Jews, as was the case when cartoons of Emmanuel Macron, carrying echoes of the 1930s, referred to his prior work at the Rothschild bank.

As for the far-left, anti-Zionist brand of antisemitism, EU-validated guidelines say: “Manifestations might include the targeting of the state of Israel, conceived as a Jewish entity. However, criticism of Israel similar to that levelled against any other country cannot be regarded as antisemitic.” A red line is crossed when criticising Israel becomes a criticism of Jews. A legal definition of antisemitism helps the authorities collect data, which is currently patchy. The EU agency for fundamental rights has now announced a new survey investigating discrimination and hate crime against Jews living in the EU.

Trump’s announcement on Jerusalem caused consternation in many parts of the world. But the events that followed in Europe should serve as a wake-up call. A diverse continent directly affected by events in the Middle East must address new realities. Acknowledging them is the first step. More efforts are needed in education, and more scrutiny on social media. Now is not the time for blinkers or awkward silence.

• Natalie Nougayrède is a Guardian columnist