DHAKA, Jan. 10 (Xinhua) -- Fresh excavations to unearth further secrets of an ancient fort city at Wari Bateswar, one of Bangladesh's major archaeological sites, were launched Saturday, local media reported Sunday.

    This is the ninth dig over the past decade at the ancient city site, which has already divulged the sub-continent's oldest silver punch-marked coins, said a report of the leading private news agency bdnews24.com.

    Inaugurating the new excavations, Bangladeshi Local Government Minister Syed Asharaful Islam, told reporters that the archaeological findings of this city, under the South country's central Narayangonj district, some 17 km away of capital Dhaka, are signs of a 2,500 year old civilization.

    "We have to hold on to that heritage," he said.

    The Archaeology Department of Bangladesh's leading public Jahangirnagar University (JU) began the excavation work at the site in 2000.

    Earlier excavations uncovered the fort city thought to be a major trading post on Bangladesh's capital Dhaka surrounding Buriganga river, dating from around 500 BCE.

    Evidence of a river port, roads and alleys have already been found at the site, along with treasures including ceramic name plates, precious stones, glass beads and coin vaults that included the priceless find of the sub-continent's oldest silver punch-marked coins.