Palestinian authorities on Monday announced the discovery of 31 first-century Roman-era tombs by workers at a construction site in the northern Gaza Strip.

The tombs were discovered near the town of Beit Lahia, at a construction site for a residential area.

Nazi Sarhan, an official in Gaza’s Ministry of Public Works, confirmed the discovery and said there was “evidence” of other graves at the site.

Officials said construction work has been halted and experts from Gaza’s Antiquities and Tourism Ministry have begun cataloging the tomb and artifacts.

One expert, who requested anonymity, said the tombs are believed to be part of a cemetery associated with the nearby Roman site Balkhia.

Last month, a 5th-century Byzantine church was reopened after years of restoration work by the Palestinian government, supported by foreign donors.