A woman was raped by a group of men in a park in what police described as a "random and sickening attack".
The victim, aged in her 20s, was attacked at about 00:30 BST at Kirkup Gardens in Wythenshawe, Manchester.
Greater Manchester Police said it was "truly horrendous" and the woman was being supported by specialist officers.
Patrols have been stepped up in the area as officers continue to search for evidence.
No arrests have been made and the force are appealing for anyone with information to get in touch.
Ch Insp Cara Charlesworth said: "At this stage, this appears to have been a random and sickening attack and our officers are working tirelessly to identify those responsible.
"In the meantime, we have increased our police presence in the area, and the public should feel reassured that if they have any concerns they can approach our officers directly."