EXCLUSIVE

Kanye West's rap prodigy 2 Chainz was arrested at LaGuardia Airport in New York today ... after cops say he was packin' brass knuckles in his carry-on bag ... TMZ has learned.

2 Chainz -- real name Tauheed Epps (who also goes by the name Tity Boi) -- was entering the Delta terminal to fly to a show in North Carolina ... when the TSA discovered brass knuckles in his bag.

Law enforcement tells TMZ ... police were called to the scene ... and 2 Chainz was taken into custody for misdemeanor possession of a criminal weapon at 1:45 local time.

2 Chainz -- famous for his hit song "Spend It" -- is still in police custody.

A rep for 2 Chainz tells us ... his team is "handling the situation."