Leicestershire Police said they had reinforced their resources and are using specialist divers in searches following reports of a two-year-old boy falling into the River Soar on Sunday.
The toddler was with family when he fell into the water, authorities confirmed.
On Monday, police said they had still not been able to locate the youngster.
Emergency services attended the scene just after 5pm on Sunday before beginning a search and rescue operation began in Aylestone Meadows, close to Marsden Lane.
A man was taken to hospital “as a precautionary measure”.
The toddler's family are being supported by specialist officers.
