The search for a missing six-year-old boy who fell into a river in Kent will continue on Sunday morning, emergency services said.

Kent police said officers were called to Richborough Road in Sandwich over concern for the welfare of a child who had fallen into the river Stour while fishing with his father.

The boy, named locally as Lucas, plunged into the water as he fished. It was reported that he wasn’t wearing a lifejacket. His father jumped in after him but the boy has not been seen since.

Kent police are leading an intensive search, which also involves water safety units, an inshore lifeboat, coastguard helicopter and Kent fire and rescue service, to find the missing boy, the force said.

The riverbed was the central focus of the search, but a number of different waterways and a scrapyard close to where boy went into the water were also being examined.

The public joined the hunt along the riverbanks and the fire service held a public meeting to brief volunteers on Saturday evening. Other people shared their support with messages of hope online.

As the search was called off after 10pm on Saturday owing to darkness, members of the public were warned about their safety if they continued to search, including working in groups and using torches.

Kent fire and rescue service assistant director Chris Colgan said: “We’re all incredibly grateful to everyone who has given everything today to try and locate this little boy. Our thoughts are with him and his family tonight at this very difficult and emotional time.

“I would like to appeal to people who have come to Sandwich to join the search – if you continue overnight please make sure your own life isn’t placed at risk.”