Security officers dealing with a suspicious device in Londonderry on Sunday came under attack from petrol bombs and fireworks.
A number of homes near the Lecky Road flyover in the city were evacuated after the discovery of the object.
The alert was later declared a hoax by army technical officers (ATO).
Chief Inspector Alan Hutton said: “I would like to thank residents in the area and members of the public for their continued patience while we worked to keep everyone safe.
“However, I would strongly condemn the actions of a small group of people who threw missiles, including petrol bombs and fireworks, at officers whose only motivation is to protect the community they serve.
“This small minority of individuals showed a complete disregard for their area and the community who live there, by attacking police this afternoon. Their actions serve no purpose other than to cause harm to our community and lead to criminal convictions for young people. Thankfully no one was injured.”
Colum Eastwood, the SDLP leader, condemned those behind the alert.
“It is absolutely disgraceful that a suspect device has been placed right in the heart of our community. Those responsible must be stopped.
“Residents are now being evacuated from their homes on a cold Sunday afternoon thanks to those behind this attack on our community.
“Those responsible achieve nothing from their actions, instead their big victory is frightening and causing disruption to local people. They need to catch themselves on.”
Mr Eastwood called on the community to try and stop future incidents.
He added: “The SDLP is working closely with the PSNI to ensure the safety of all in the area.
“I urge anyone with any information to bring it forward immediately to the authorities.
“There’s only one way to stop these attacks, that is for all of in our community to unite and speak out against those who seek to drag us back to the past.”