UNDATED (CNN) -- Olympic officials in London gathered Monday to remember the terrorist attack during the 1972 summer games in Munich. Monday's commemoration was hosted by Israel's Olympic committee.

With IOC officials in attendance, widows of two of the 11 Israeli athletes killed in Munich spoke out, denouncing the international committee.

The widows are upset with the IOC for failing to offer a moment of silence during opening ceremonies.

Forty years ago, at the 1972 Olympic Games in Munich, 11 Israeli athletes were taken hostage and murdered by the Palestinian terrorist group Black September.

Now, in the midst of the London 2012 Olympics, friends and relatives of those athletes gathered in central London for a memorial service.

Among them was Ankie Spitzer. Her husband, fencing coach Andre Spitzer, was one of the people killed in the attack. She recalls entering the house where the Israelis were held hostage in the days after the crisis. She says, "One of his fencing students came with me to the front door and said don't come up and I said I want to see what happened so I went up by myself and stood in the room. The chaos was incredible. There was blood all over the place. There were huge holes in the wall, half of the wall had come back into the room. They brought them food they could not eat. They didn't let them go to the bathrooms. It was total chaos but I thought if this was where they spent the last moments of their lives I am going to talk about it."

Spitzer campaigned to have the athletes' deaths formally recognized by a minute's silence at the opening ceremony, but that request was denied. But a moment of silence was observed at a smaller event within the Olympic village, attended by British Prime Minister David Cameron. The Olympics are about athletic achievement and competition but also international goodwill. Cameron says, "A sickening act of terrorism that betrayed everything the Olympic movement stands for and everything that we in Britain believe in. So as the world comes together in London to celebrate these remarkable Olympic Games and all of the values that the Olympic Games represent, it is right that we should stop and remember the 11 Israeli athletes who so tragically lost their lives when those values came under attack in Munich 40 years ago."

Also there the mayor of Munich's Olympic Village Walther Troger. In 1972, he spent hours negotiating with the terrorists and says he knew they were prepared to kill and be killed to further their cause. He says, "Issa, the chief told me more times, there's no other way. Don't try, I am a soldier and I have an order. I have to fulfill that order. I might not survive, I am sure I will not survive, maybe that was the beginning of the suicide people. You offer us a window and this window we must use to show the situation of our people."

Friends and relatives hope that by remembering the horror of what happened 40 years ago, it will never be repeated.