Commercial Fixed Wing
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Distraction; Workload
Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Passenger Misconduct
General None Reported / Taken
Environment - Non Weather Related; Human Factors
Approximately 3 hours into flight a group of 3 passengers would not comply with the Flight Attendant instructions regarding wearing their face masks.  She notified us and we told Dispatch of the situation and their seat location.  Shortly after; they became belligerent to the flight attendants and continued [with] non-compliance.  Now they were using foul language and disrupting other passengers.  The Captain asked one of the foreign language speaking flight attendants to go try and deescalate the situation but that only made things worse.  We looked in the Flight Operations manual and technically this was a threat level 1.  We discussed whether should we notify Dispatch and we agreed by the definition it was; but we did not really think this was anything other than a couple of intoxicated passengers.  The Captain got on the PA and addressed the cabin of the importance of wearing the mask.  After this announcement we had no further trouble with these passengers. They apologized to the Flight Attendant as they exited the plane in ZZZ.Mask requirements in cabin; possible intoxication; lack of respect for airline rules. As soon as the Captain made the announcement this problem went away.  Maybe we should have tried that sooner.
Air Carrier First Officer reported 3 passengers would not comply with the face mask policy during flight and became belligerent toward the flight attendants.