A museum in Los Alamos, New Mexico — a once-secret New Mexico city that developed the atomic bomb which helped end World War II — has put an exhibit from Japan on hold because of its theme of abolishing nuclear weapons.

The Los Alamos Historical Museum confirmed Monday that it will not host a traveling exhibit organized by the Hiroshima Peace Memorial Museum and Nagasaki Atomic Bomb Museum until all parties can work out their differences over the theme.

The exhibit, which features articles of clothing, exposed plates, and other personal items from victims, aims to draw attention to the horrors of the bombs that destroyed both cities.

Heather McClenahan, executive director of the Los Alamos Historical Museum, said the museum’s board of directors felt uncomfortable about the exhibit’s call to abolish nuclear bombs. The New Mexico city is still home to the Los Alamos National Laboratory, one of the U.S.’s premier nuclear weapons research centers.