Police in Montgomery County arrested 15 persons in coordinated raids yesterday and seized an undetermined amount of drugs in response to what authorities called a recent increase in the local availability of crack, a highly potent and addictive form of cocaine.

"Crack has established itself in Montgomery," county police Sgt. Wayne Cleveland said at a news conference after early-morning raids on five Rockville apartments, involving an estimated 100 county and Rockville police officers and federal agents. "There's a demand for crack here now, and we expect nothing but to see it keep growing."

County police Lt. Ronald Ricucci said undercover officers have made numerous purchases of crack from dealers, some from New York, operating for several months in four apartments at David Scull Courts on Lenmore Avenue, a public housing complex owned by the city, and at an apartment at the Lincoln Park complex on First Avenue.

He described David Scull Courts as "a classic crack market," with buyers and sellers coming and going at all hours.

In simultaneous raids beginning about 5:30 a.m., Ricucci said, officers arrested eight men, five women and two 17-year-old youths and charged them with various drug offenses. He said the officers confiscated three pistols, an undetermined amount of crack and cocaine, a few thousand dollars in cash and several stolen television sets and videocassette recorders that drug dealers had accepted as payment.

He said some of those arrested were dealers, others buyers, and others were residents being paid by dealers for the use of their apartments.

The suspects, ages 17 to 32, offered no resistance, Ricucci said. About an hour before the raids at David Scull Courts, he said, one of the youths -- who was later arrested -- fired six shots at a woman in an apparent dispute over a drug deal. The youth was charged with attempted murder, he said. The woman was not injured.

He said detectives had charged other suspects with possessing crack recently, but yesterday's arrests were the first involving an organized group of high-volume dealers.