Israeli tourists traveling on a cruise ship were prevented from disembarking at a stop at the Port of Tunis.

The Israeli passengers were told quietly by staff aboard the Norwegian Jade that they were not welcome per the Tunisian government during the stop, B’nai Brith Canada said in a statement Sunday. The organization had been contacted by a Jewish Canadian passenger on the ship.

There were about 20 Israelis on board the ship, according to Haaretz. They did not know in advance that they would be required to remain on the ship during the day-long stop.

Jewish passengers who were not Israeli were permitted to disembark in Tunis.

“The cruise line had a responsibility to its passengers and advise them of this discriminatory policy in advance. Better still the cruise line should avoid ports that have such policies,” B’nai Brith Canada’s CEO, Frank Dimant, said in a statement.