A Las Vegas man allegedly slit his ex-girlfriend’s throat with a box cutter in a casino — leaving her with 30 stitches, according to a report.

Kem Peters, 33, has been charged with attempted murder, burglary and domestic violence and battery in the gruesome Feb. 5 early-morning attack at the Westgate Hotel – just one block away from the packed Strip, according to an arrest report obtained by the Las Vegas Review-Journal.

Peters, who has two prior domestic violence convictions, approached the woman near the front lobby of the casino. She and Peters had been in a relationship for four years before separating two months ago, she told police.

“Peters pulled a box cutter from his pocket in right hand and told [the victim], ‘Now I’m going to slice your neck,’” according to the arrest report.

The victim was shoved to the floor, where Peters quickly pounced on her, police said.

“Peters jumped on [her] and sliced her neck,” the report continued.

A witness who saw the assault tried to intervene, but was punched in the mouth. The attacker, identified as Peters by his ex-girlfriend, then sliced the man in the face, leaving him with a gash that needed four stitches, police said.

Peters’ ex, meanwhile, was sliced with the box cutter “from below her ear to the front of her neck,” a wound that required a total of 30 stitches when she was treated at a hospital, police said.

It’s unclear where Peters was taken into custody following the alleged attack. He declined to talk to cops when he was arrested, the newspaper reports.

A message seeking comment from Las Vegas police was not immediately returned early Wednesday.

Peters — who has four prior domestic violence arrests, resulting in two convictions — remains held without bail at the Clark County Detention Center. His next date in court is Feb. 24, records show.