Federal agents arrested seven Northern Virginia residents yesterday, saying the defendants ran one of the Washington region's largest crack distribution networks and sold as many as 25 kilograms of crack and cocaine each week.

The undercover operation with local and federal law enforcement officials also seized 10 kilograms of crack, four kilograms of cocaine, several automatic weapons, $50,000 in cash and 10 cars that were allegedly used to transport the drugs.

"With respect to crack, that's one of the largest seizures in the country," said U.S. Attorney Henry E. Hudson, whose office assisted a team of investigators from the Drug Enforcement Administration, the Immigration and Naturalization Service and local and Virginia State Police.

Hudson said the investigation began modestly a year ago, and escalated quickly when an undercover officer "infiltrated" the drug network and determined that it was responsible for a sizable portion of the cocaine being brought to Washington from New York.

Those arrested were Arlington residents Bobby Eugene Pope, 44, Jose Cabrera, 28, Romulo Deleon, 22, and Reina Dawkins, 30; Crystal City residents Francisco Polanco, 31, and Terry Wiggins, 32; and Edwin Rodriguez, 20, of Falls Church.

Pope, who owned a private detective agency, helped rent apartments in Northern Virginia that were used by the defendants to stash shipments of cocaine, according to law enforcement officials.

All the suspects have been charged with conspiring to sell more than 50 grams of cocaine and are being detained in Alexandria City Jail. If convicted, each defendant faces a maximum prison sentence of at least 10 years without parole.

The suspects are scheduled to appear before a federal magistrate today for a bond hearing.

Con Dougherty, spokesman for the DEA, said the group brought cocaine to Washington from New York, using secret compartments built into several family-style cars that were meant to be inconspicuous.

A 1983 Mercury station wagon had been outfitted with a hidden compartment capable of carrying up to 50 kilograms of cocaine, Dougherty said.