Cigar aficionados beware: Those handmade Montecristos, Cohibas and Romeo y Julietas may not be the premium smokes they seem.

Law enforcement and cigar industry officials say counterfeiters are marketing millions of dollars in fake upscale cigars, some even pretending to be authentic Cubans that are illegal to sell in the United States. A recent crackdown has uncovered several major counterfeit operations, including one in Miami that resulted in the seizure of more than $20 million in fake stogies, labels and packaging.