The Swiss president insisted Monday that "anti-Semitism has no place in Switzerland", after the brutal stabbing over the weekend of an Orthodox Jewish man, allegedly by a teenager pledging allegiance to Islamic State.

"The knife attack in Zurich shocked me," President Viola Amherd wrote on X, adding that her thoughts were with the victim and all Jewish citizens in the country.

Her comment came after the 50-year-old Orthodox Jewish man was stabbed in Switzerland's largest city late Saturday, with police initially saying he had been "critically injured".

The Swiss Federation of Jewish Communities however told the Swiss news agency Keystone-ATS news agency Monday that the man's life was no longer in danger.

A police statement on Sunday said the motives for the attack remained unclear but that investigators were looking into the possibility that it was an "anti-Semitic crime".

A 15-year-old Swiss boy with a Tunisian background is suspected of carrying out the attack, the youth prosecutor's office said Monday, adding that it was holding him in custody.

The suspect had made a video claiming responsibility for the attack, Zurich cantonal police chief Mario Fehr confirmed during a press conference.

In the video, the teenager voices his allegiance to the Islamic State jihadist group and called for fighting Jews around the world, police said, according to Keystone-ATS.

The youth prosecutor's office meanwhile said investigators were looking into whether or not the attacker acted alone.

Police in Zurich announced Sunday they were hiking security around Jewish institutions as a "precautionary measure".

The Zurich-based Foundation Against Racism and anti-Semitism condemned the attack, saying that witnesses had heard the alleged perpetrator shout "anti-Semitic slogans that suggest a hate crime".

"It was not just an isolated case," it said in a statement. "Since the escalation in the Middle East, anti-Semitic incidents in Switzerland have skyrocketed."

Anti-Semitic and anti-Muslim hate crimes have been on the rise in many countries since Hamas militants from Gaza carried out an unprecedented attack inside Israel on October 7.

That attack resulted in the deaths of about 1,160 people, mostly civilians, according to an AFP tally of official figures. It also saw the militants abduct 250 hostages, of whom 130 remain in captivity, including 31 presumed dead, according to Israel.

Israel's retaliatory offensive against the Palestinian territory has killed more than 30,500 people, mostly women and children, according to the health ministry in Hamas-run Gaza.