The incident happened as a woman was with her daughter and her dog in The Mount, Ringwood, Hampshire, between 10.40am and 10.50am on Wednesday.
A Hampshire police spokesman said: ‘A woman and her two-year-old daughter were approached by two men who showed an interest in her dog.
‘The woman reported that one of the men then picked up her daughter and ran with her towards a nearby housing estate. The child was let go after the dog bit the man on his leg.
‘The young girl, and her mother, are being supported by specialist officers who are at this early stage trying to ascertain the exact circumstances of what happened and they are currently dealing with it as an attempted kidnapping.’
The two men were white, in their late 30s, both about 5ft 7in, wearing caps – with one wearing light blue jeans and the other dark jeans.
Detective Inspector Janine Bradley said: ‘We fully appreciate that this incident will have a significant impact on the community, and we want to reassure the public that we are taking this report very seriously.
‘Our officers are carrying out extensive inquiries in the local area – including house-to-house visits, scoping CCTV and there will be high-visibility patrols in the area to reassure the community.’