According to media reports, on 29 October, a Swiss guard is said to have made disparaging remarks about Jewish guests present at the general audience and made a spitting gesture in their direction.
The exact course of events is still unclear; according to a spokesperson for the Swiss Guard, the incident is being investigated.
They are in contact with those involved.
The reports were triggered by an account by the German theologian Gregor Maria Hoff, who teaches in Salzburg, in the Austrian church newspaper "Die Furche".
Later, a Jewish participant affected by the incident also reported that there had been an "act of spitting in her direction".
The guardsman had previously said "les juifs" (the Jews) in French and in a derogatory manner.
Special occasion
The alleged incident took place on the sidelines of a general audience at which Pope Leo XIV emphasised the Catholic Church's commitment to combating all forms of anti-Semitism.
The reason for the Jewish delegation's visit was a three-day congress in Rome to mark the anniversary of the Council document "Nostra aetate" of 28 October 1965, in which the Catholic Church placed its relations with Judaism and other religions on a new basis of respect.
According to the Swiss Guard spokesperson, the investigation into the events of 29 October will take "some time".
There is a standard procedure for allegations against guardsmen, which will also be applied in this case.
If the allegations are confirmed, disciplinary sanctions are possible in the Swiss Guard, as in any army.