A man had to have seven stitches in his arm after he was attacked on the Racecourse in Northampton.
The 21-year-old was walking across the park at about 1am today (Tuesday, March 10) when he was assaulted.
He was close to the basketball courts when he was attacked from behind by at least two people.
He was left with a cut to his arm that required stitches.
Witnesses, or anyone with any information about this incident, can call Northamptonshire Police on 101.
Alternatively, they can call the independent charity Crimestoppers anonymously on 0800 555 111 or use the anonymous online form at www.crimestoppers-uk.org.