Bottles were thrown at police in Ballyclare as they dealt with about 100 youths who were drinking alcohol and "causing a nuisance".
Officers were called to an area near the bridge in Main Street on Saturday evening after reports about the behaviour of the the youths, aged between 12 and 17.
The attack happened as they helped an "intoxicated young female", they said.
She had hurt herself and police had to accompany her to hospital.
"Not only are police concerned about the intoxicated state of some of the young people but also by their actions, which could ultimately result in a criminal record," said a PSNI spokesperson.