Updated

Israel's antiquity authority says vandals have badly damaged a 1,600-year-old mosaic in the northern city of Tiberias.

Authority archaeologist Gilad Kinamon says the mosaic once formed the floor of a 4th century synagogue. He says vandals smashed parts of the mosaic, grinding it to a fine powder, while other parts were badly scratched.

Kinamon says the mosaic was unique for its time because it illustrated the zodiac signs and listed the names of the synagogue's chief patrons in ancient Hebrew, Latin and Greek.

He says the mosaic found damaged early Tuesday was in a fenced-off enclosure that was not guarded overnight.

An Israel police spokesman said they opened an investigation into the incident.