Athens (CNN) -- Robbers broke into a museum in Olympia, the birthplace of the Olympics, tied and gagged a museum guard, and fled with stolen artifacts, Greek authorities said Friday.
The two men raided the Museum of the History of the Olympic Games, a smaller building close to the main Archaeological Museum of Olympia, just after 7:30 a.m. local time, said Athanassios Kokkalakis, a police spokesman.
The robbers "approached the museum's guard, tied her hands and bound her mouth and then went into the museum, where they took 65 to 68 small clay and brass small statues, and a gold ring, and put them in a bag and left."
Culture Minister Pavlos Geroulanos submitted his resignation after the robbery took place, the prime minister's office said.
Geroulanos' office said his offer to step down not yet been accepted. The minister is on his way to Olympia to view the scene of the robbery.
It is the second big theft of this kind this year in Greece.
In January three art works, including a painting by Pablo Picasso and another by Piet Mondrian, were stolen from the National Gallery in Athens.
Dimitra Koutsoumba, president of the Greek Archaeologists' Association, said the latest attack was a sad and worrying incident.
"It is the first time that we have an armed robbery at a museum during operating hours. It shows that the cuts the Culture Ministry has made since the crisis hit in 2009 make it easier for such incidents to take place," she said. "The minister himself had told us that the cuts were ranging between 30% and 35%, and they include cuts in personnel."
She called for more importance to be placed on cultural heritage and said greater steps should be taken to protect irreplaceable items that belong to the nation.
"Such incidents are an issue of national security," she said. "The artifacts that were taken were mainly figurines related to the Olympics, so many were depicting athletes."
The museum, built on an ancient site in the Peloponnese peninsula, is considered among the most important in Greece.
The ceremony for the lighting of the Olympic flame for the 2012 London Olympics is scheduled to take place on May 10 at the Ancient Olympia site, where the museum is located.
The first Olympic Games were held in Olympia in 776 B.C. to celebrate the deity Zeus. A sanctuary at the site was dedicated to him.