Greece moved Monday to try to obtain newly surfaced photos that appear to depict the execution of 200 Greeks by a Nazi firing squad in Athens during World War II, after the images were listed for sale online. Greece’s Culture Ministry said the photographs were posted for sale on Saturday by a collector in Belgium and that it will seek to acquire them as historical archives if they are both authentic and legally obtained.

The ministry said its assessment could not be finalized immediately, but it also said it is “very possible that these are authentic photographs.” It said experts from the ministry were already in contact with the Belgian collector and planned to visit him in Ghent to examine “the authenticity and legality of origin.” A ministry committee was also set to convene Wednesday to determine whether to classify the photographs as part of Greek heritage.

The online listing appeared over the weekend, and the images were described as showing men being led to their deaths at a shooting range in the Kaisariani suburb of Athens. The ministry said the pictures allegedly show the men being marched through a gateway and down a path before they were lined up in front of a wall. The listing asserted that the executions took place on May 1, 1944.

In Greece, the Kaisariani executions of 200 communist political prisoners are widely remembered as among the worst atrocities during the Third Reich’s occupation of Greece. Greece’s Culture Ministry said the images have historical significance, but it also emphasized that acquiring them could require addressing legal complications tied to their chain of custody and provenance.

After the photographs were posted for sale, a memorial at the Kaisariani site was vandalized, the Kaisariani municipality said. The municipality said plaques listing names were smashed shortly after the listing went live, and it linked the vandalism to the anger or distress caused by renewed attention to the killings. In a statement posted to its Facebook page, the municipality said “Historical memory will not be erased, no matter how much it bothers some people,” and said it would repair the monument.

The Culture Ministry said there were “quite a few legal complications” in how Greece could lay claim to the photographs. It said the next steps would depend on the findings of experts who would assess whether the photos are genuine and whether they were obtained lawfully.

The ministry said that if experts determine the photographs are both authentic and legally obtained, “the Culture Ministry will immediately finalize the measures for their acquisition through the appropriate legal means,” bringing the matter back under Greek authority for archival preservation and heritage considerations.