London (CNN) -- The head of the International Olympics Committee again rejected calls for a moment of silence during the Games' opening ceremony to honor Israeli Olympians killed in a terror attack at the 1972 Games.
"We feel that the Opening Ceremony is an atmosphere that is not fit to remember such a tragic incident," Jacques Rogge, the president of the International Olympic Committee, said Saturday.
Ronald Lauder, the president of the World Jewish Congress, condemned that stance Sunday as "unfeeling" and "completely out of touch."
More than 100,000 people have signed an online petition calling for a moment of silence in memory of the 11 Israeli athletes and coaches killed by Palestinian militants at the games in Munich, Germany, 40 years ago. A German policeman and five of the attackers also died.
President Barack Obama supports the campaign, the White House said Thursday.
Read more: Obama says yes to Olympic tribute
Israel's Deputy Foreign Minister Danny Ayalon has also been a vocal proponent, campaigning on Facebook and Twitter for "Just One Minute" of silence.
The refusal of the IOC to back the plan "told us as Israelis that this tragedy is yours alone and not a tragedy within the family of nations," Ayalon said in May.
Ankie Spitzer, whose husband Andrei was among those killed, was the first to sign the petition.
"They came to Munich in 1972 to play as athletes in the Olympics; they came in peace and went home in coffins," she writes in the online plea.
She says she has "no political or religious agenda. Just the hope that my husband and the other men who went to the Olympics in peace, friendship and sportsmanship are given what they deserve. One minute of silence will clearly say to the world that what happened in 1972 can never happen again."
Rogge said Saturday that the IOC would "be present" at the September 5 ceremony honoring the dead at the site where they were killed in Germany.
"We are going to pay a homage to the athletes, of course, as we always have done in the past and will do in the future," he said.
But Lauder of the World Jewish Congress said that was inadequate.
"Frankly, that's not good enough," he said, arguing that "hardly anybody" will notice that event.
The attack began in the early hours of September 5, 1972, when eight Palestinian terrorists disguised in track suits broke into the Olympic Village in Munich.
Read more: Can we feel safe in a crowd anymore?
They stormed the apartments housing Israeli athletes and coaches, killing two and taking nine others hostage. Hours later, the world woke up to the image of a masked man on the balcony of the Olympic Village.
From the Olympic Village, the militants demanded the release of 200 Arab inmates from Israeli prisons or they would start killing the athletes in Munich, one every hour.
Israel refused to negotiate, and the terrorists demanded an airplane to Egypt. The German government then attempted a rescue at the airport. When it was over, all the Israelis, five terrorists and one German police officer lay dead.
The Munich Games were temporarily suspended, and a memorial service attended by some 80,000 people was held at the Olympic Stadium.
CNN's Chelsea J. Carter contributed to this report.