Police arrested a man after he allegedly assaulted his ex-girlfriend with a possible box cutter in Kakaako early today.

Police said the suspect and the victim were involved in an argument at an establishment at about 12:30 a.m. when he brandished a small and sharp dangerous instrument.

He struck the victim, causing a laceration to her head. The injury was non-life-threatening and she was transported to a hospital in stable condition.

Police said a witness saw the suspect use slashing movements toward the victim. Though witnesses couldn’t positively identify the type of dangerous instrument the assailant used in the attack, responding officers recovered a box cutter at the scene.

Police arrested the suspect on suspicion of second-degree assault.