Extension works at the Kerċem parish priest’s home have led to the discovery of two tombs believed to be 5,000 years old.
The rock-cut tombs, one of which still contained fully articulated skeletons, were found next to the house which lies adjacent to the parish church, the government said.
Pottery recovered from the site so far place the origins of tombs in the Tarxien phase of Maltese prehistory, dated to about 3000-2500 BC.
The excavations are being carried out by the Superintendence of Cultural Heritage under the direction of Anthony Pace.
The tombs may have been first encountered during the construction of Kerċem parish church, between 1846-51, which involved extensive quarrying. However, the tombs did not draw any further attention and went unnoticed for another 163 years.
It emerged yesterday that the tombs were exposed again when the site was being cleared of debris in 2008.
The Superintendence immediately took steps to protect the site and a temporary cover was installed to provide shelter from the rain. The site was monitored and allowed to dry for an entire year. Archaeological excavations and anthropological investigations began last July.
The rock-cut chambers have a circular plan and may have been accessed through a special shaft or a roof entrance. One of the chambers has a small annex.
The government said rock-cutting techniques used at the Kerċem tombs were reminiscent of those used at the Ħal Saflieni hypogeum. The grave diggers used drilling and levering techniques to crack stone and carefully shape the burial chambers.
Several drill holes can still be seen in the chamber walls, which were also smoothened down, perhaps by means of hard pebbles. A small rock-cut column marked the entrance to the small annex whose floor is lower than that of the main chamber.
Future investigations will focus on pathology, on carbon-dating and if possible, on the more elusive DNA of the human remains.
The government said the tombs would become the central feature of a small community museum now planned for the site.
The Superintendence is working closely with Church authorities to design a small permanent exhibition featuring this discovery.