An organization of European Jews that wants to sail an aid ship to break the Israeli blockade of Gaza said Wednesday its ship was ready to go, but its port of departure remained a secret.

Kate Katzenstein-Leiterer, a leader of the German Jewish Voice organization, said the trip was being managed by Jews for Justice for Palestinians (JfJfP), a British group. The Jewish activists were already on board.

Open gallery view Demonstrators in Zurich protesting against Israel May 4, 2010 in wake of Gaza flotilla raid. Credit: AP

She said detailed information about the voyage would be released the day the boat casts off, but she did not say when this was.

Katzenstein-Leiterer grew up in the former East Germany, to where her committed Communist parents returned after fleeing Hitler's regime in World War II.

Her organization is part of the European Jews for a Just Peace movement, a 10-country peace-activist network.

Jewish Voice in Germany says that it has gathered the funds for its aid ship project from personal donations, loans, and a donation from the Left Party, a party with strong support in the former East.

Earlier, Katzenstein-Leiterer said her group's stance has caused them to be ostracized by the mainstream German-Jewish community, which numbers a little over 100,000.

On May 31 nine people were killed when Israeli naval forces boarded ships in a flotilla carrying aid and activists - some of whom Israel says were armed - bound for the Hamas-ruled Gaza Strip.