Amber Portwood's Missing Fiancé Possibly Spotted in Oklahoma, Police Say

Amber Portwood's fiancé, who was reported missing, might be several thousand miles away from his last known whereabouts ... TMZ has learned.

Bryson City PD Asst. Chief Wayne Dover tells TMZ ... Gary Wayt, who's been engaged to the "Teen Mom" star for the last few weeks, is still considered a missing person -- but there's currently no reason to suspect foul play or a potential suicide.

In fact, we're told there's been a reported sighting of Gary this week -- the MTV personality's beau allegedly popped up Tuesday morning in Weatherford, Oklahoma, according to Asst. Chief Dover ... who adds, the person witnesses claim was Gary did not seem in distress and had a calm and nonchalant demeanor.

Cops say the man even identified himself to the purported witness as Gary while chatting it up with someone in town ... and was seen doing normal activities.

He was reportedly spotted again just west of Weatherford, and was observed simply going about his day ... not upset in the slightest.

Still, Asst. Chief Dover says the sightings have not been 100% confirmed yet by law enforcement -- so he's still considered MIA ... but it's the first sign he's alive and well.

Remember, Gary was last seen by Amber Sunday evening in their hotel in North Carolina ... leading the TV star to panic about his whereabouts and file a missing person's report.

We're told Bryson City PD has been in touch with the FBI and North Carolina State Bureau of Investigation for assistance in the case.

Amber later declared on social media she was worried about Gary ... revealing her fiancé took his keys and wallet, but not his phone. She admitted they had a discussion before he left, but assured fans it "was not a big blowout fight or anything like that."