Updated at 8:41 p.m.:

Police arrested 30 people in a drug-arrest operation in York City Wednesday.

It also resulted in the confiscation of an undetermined amount of drugs, guns, cash, and weapons, said Trooper Robert Hicks, state police spokesman.

A press conference on the operation has been scheduled for Thursday morning, according to a news release from York County.

Previously reported:

A helicopter flying over York City during rush hour Wednesday morning was being used to assist police in apprehending dozens of alleged drug dealers.

The operation was the culmination of an 18-month investigation and the service of 80 arrest warrants, said Trooper Rob Hicks, state police spokesman.

The roundup began early Wednesday morning and will continue until all 80 suspects are located, according to York County District Attorney Tom Kearney.

He said state police are conducting raids with the York County Drug Task Force and numerous other law-enforcement agencies to arrest people involved in the city's drug trade.

Kearney and Hicks declined to disclose further details about the investigation. A press conference is set for 11 a.m. Thursday at the state police barracks in Loganville.