Huynh Dinh Quoc Thien, director of the Danang Museum, said on October 21 that specialists were excavating the cannon discovered during a project to restore and preserve the historic citadel.
The cannon was found at around 9 am on October 21, buried beneath an area undergoing landscaping work. Initial examination showed it measured 2.95 metres in length and was made of cast iron.
Thien said the weapon may have belonged to the Nguyen Dynasty's defensive arsenal at Dien Hai Citadel and could have been used during the resistance against French and Spanish forces in Danang between 1858 and 1860.
The artefact is being excavated and documented for preservation and further research to establish its origin.
Built in 1813, Dien Hai Citadel in Danang's Hai Chau Ward played a significant role in the city's resistance to foreign invasion.
It was designated a national historical relic in 1988 and recognised as a special national relic in 2017.