during the war, the icrc failed to obtain an agreement with nazi germany about the treatment of detainees in concentration camps, and it eventually abandoned applying pressure to avoid disrupting its work with pows. the icrc also failed to develop a response to reliable information about the extermination camps and the mass killing of european jews. this is still considered the greatest failure of the icrc in its history. after november 1943, the icrc achieved permission to send parcels to concentration camp detainees with known names and locations. because the notices of receipt for these parcels were often signed by other inmates, the icrc managed to register the identities of about 105,000 detainees in the concentration camps and delivered about 1.1 million parcels, primarily to the camps dachau, buchenwald, ravensbrück, and sachsenhausen.