NEWPORT — A five-month federal and local undercover investigation of a drug trafficking ring netted 18 arrests yesterday in the North End of the city, with warrants still outstanding for 8 additional suspects.

Two of the defendants, Wayne M. Perry, 37, aka “Fats,” of 21 Park Holm, and Travis T. Sims, 26, aka “Ace,” of Apt. A, 17 Newport Ave., were arraigned yesterday in U.S. District Court in Providence.

Travis pleaded not guilty to an indictment charging him with two counts of distributing 5 grams or more of crack cocaine and an additional count of delivering crack cocaine, according to a spokesman for U. S. Attorney Clark E. Corrente.

Perry, who has been indicted on two counts of delivering crack cocaine, also pleaded not guilty, said spokesman Tom Connell.

The names and charges of the other defendants, most of whom face charges in the Rhode Island court system, were not available yesterday.

Police Sgt. Anthony J. Chauvin, head of the Newport vice and narcotics unit, said yesterday’s raid capped an undercover probe of sales of crack cocaine and prescription drugs that combined the efforts of the police, the federal Drug Enforcement Agency and the federal Bureau of Alcohol, Tobacco and Firearms.

Beginning at 8 a.m. yesterday, a total of 20 to 25 law enforcement officers hit four locations in the North End, Chauvin said.

The sweep stopped at Perry’s and Sims’ homes, as well as 14 Hall Ave. and 42 Park Holm, according to law enforcement officials.

Chauvin said late yesterday afternoon that most of those arrested earlier in the day had not yet been arraigned.

gmacris@projo.com