A toddler and his father were injured after a "nasty" confrontation in a pub.
The victims were at a family party at the Yew Tree Inn, Chalvington, near Polegate, when a fight broke out.
One man pushed another who fell onto the toddler, causing him head and cheek injuries that he went to hospital for.
When the child's 33-year-old father then challenged a group of men and women about what had happened he was knocked to the ground and kicked. He suffered bruising to the face.
The first suspect was a slightly overweight white man with scruffy ginger hair who was 5' 10" or 5' 11". He was unshaven and wearing a white or cream t-shirt and shorts.
The second suspect was a white man with short brown hair who was slim and 5' 8" or 5' 9". He was wearing a white t-shirt and shorts.
PC Nikki Desouza said: "This is a nasty case involving a young child being assaulted, receiving facial injuries, and also his father when he has intervened. I would ask anyone with any knowledge to please come forward."
Anyone with information should email firstname.lastname@example.org quoting serial 525 of 28/07, call 101 or contact the independent charity Crimestoppers anonymously on 0800 55511