Archaeologists working at the site of Amphipolis, northern Greece, on Friday gained access to the third chamber of the massive tomb.
The site workers entered the chamber after removing a large volume of earth behind a wall bearing the two sculpted female figures, or caryatids, that were uncovered over the weekend.
According to a Culture Ministry statement issued on Thursday, the statues are of “exceptional artistic quality.”
In comments to reporters on Friday, the ministry's general secretary Lina Mendoni
described Greece's "cultural reserves" as "a massive power" for the country.
The Amphipolis excavation has fueled intense media attention as the site dates to the era of Alexander the Great’s death and some archaeologists have suggested relatives of the warrior king might be buried ther.