(JTA) - At a ceremony held on the air base where 11 Israeli athletes and coaches were murdered during the 1972 Munich Olympics, German officials apologized for the "lack of protection" that led to the tragedy and agreed to establish a joint research commission to look more deeply into the events surrounding the terror attack.

"We cannot make amends for what has happened," said German President Frank-Walter Steinmeier on Monday. "I ask you, as the head of state of this country and on behalf of the Federal Republic of Germany, for forgiveness for the lack of protection of the Israeli athletes during the Olympic Games in Munich and for the lack of clarification afterwards; for the fact that what happened could happen."

Germany also reached a compensation deal of about $28 million with the attack's surviving family members days before the commemoration, a significant increase from a previous offer that staved off a planned boycott of the ceremony by the victims' families.

"Today, 50 years on, many questions, far too many questions, remain unanswered," Steinmeier said. "The attack was followed by years, of decades of silence and blocking out... that too is a failure. 

"Honored family members, I cannot fathom what suffering, what pain you've been through... How can life go on," he added. "For five decades, that gnawing pain has been with you."

Israeli President Isaac Herzog, who threatened to join the boycott, attended Monday's ceremony and addressed the Bundestag, or Germany's parliament, on Tuesday, praising its government for the apology and welcoming a proposal by Bundestag President Bärbel Bas to create a new German-Israeli youth exchange organization. 

Herzog thanked Steinmeier and German Chancellor Olaf Scholz for "taking responsibility" and contributing to "some relief of the pain that relatives still have today."

On Sept. 5, 1972, eight terrorists from the Palestinian group Black September entered the Olympic Village and took members of the Israeli delegation hostage, demanding the release of Palestinian political prisoners held in Israel and elsewhere. After a botched rescue attempt, 11 Israelis and one West German police officer were killed by the end of the night. 

Herzog capped his trip with a visit to the memorial at the Bergen-Belsen former concentration camp. His father, Chaim Herzog - who would become Israel's sixth president - helped liberate the camp in April 1945, as a British army officer.