Police in Venice are investigating the source of a phosphorescent green liquid patch that appeared on Sunday in the city’s famed Grand Canal.

The governor of the Veneto region, Luca Zaia, posted a photo of the green liquid that spread through the water near the arched Rialto Bridge.

The patch was reported by residents.

Italy Venice Grand Canal
A firefighter on a boat near the arched Rialto Bridge along Venice’s historical Grand Canal as a patch of phosphorescent green liquid spreads in the water (Vigili Del Fuoco via AP/PA)

Images on social media showed a bright patch of green in the canal along an embankment lined with restaurants.

Mr Zaia said that officials had requested that the police investigate to determine who was responsible.

Environmental authorities were also testing the water.