Abdelaziz -- who runs Dominance MMA -- got into it with Abe Kawa, Vice President of First Round Management, during a PFL event at the Mandalay Bay on Friday.
We're told ... Las Vegas Metro Police Dept. officers were on scene when the two got into a heated verbal altercation, which escalated into a physical incident.
Law enforcement sources tell us officers on scene say they witnessed Abdelaziz deliver two "open palm strikes" -- aka slaps -- to Kawa's face.
Abdelaziz was NOT arrested, but he was detained and cited on scene ... and if the case moves forward, he'll be notified to appear in court.
Footage of the incident was posted on social media. UFC star Anthony Pettis, Kawa's client, was in the middle of the action and told ESPN's Marc Raimondi "Abdelaziz slapped Kawa 'like a bitch' and 'was gone in 15 seconds.'"