By GARY FIELDS

At least 30 cities are expected to announce Monday that they are joining an unorthodox crime-fighting program that relies on persuasion, rather than arrests, to cut down on criminal behavior.

The initiative, run by the John Jay College of Criminal Justice, targets violent crime and open-air drug markets that are the scourge of some communities. The program is potentially controversial because it involves not prosecuting known offenders if they agree to quit their criminal activities.

The National Network for Safe Communities, which is slated to be unveiled at the annual meeting of the U.S. Conference of Mayors, will be run in cities including Boston, Cincinnati, High Point, N.C., Los Angeles, Milwaukee and Providence, R.I., where the mayors' gathering began Friday.

Developed by David Kennedy, a criminologist at John Jay College in New York, the crime program combines elements of initiatives run in the 1990s in Boston and in High Point in 2004 that were credited by authorities with helping reduce youth gang and drug violence. Boston authorities say their program cut youth homicides by two-thirds and homicides citywide by half. The High Point plan eliminated drug markets citywide, the city says.

Under the project, law-enforcement officials and prosecutors in the cities identify individuals operating in violent-crime areas who haven't yet committed serious violent crimes, and build cases against them, including undercover operations and surveillance. The culmination is a "call in" when the case is presented to the would-be suspect in front of law enforcement, community leaders, ex-offenders and friends and family.

"The prosecutor talks to them and lets them know: 'we could arrest you now but we won't because the drug dealing stops today, the violence stops today,'" said Jeremy Travis, president of John Jay. "If you continue, you now know the consequences and you've seen the case against you but we don't want to send you to prison."

Meanwhile, violent criminals who are identified will be arrested. In the High Point project, drug dealers weren't included in the program if they had a history of violence; had gun violations that were considered dangerous; or had pending cases against them.

The goals are to cut violence in neighborhoods where it has remained high despite drops nationally; lower tension between police and minority communities; shut down open-air drug markets and reduce incarceration rates. Mr. Travis said the hope is the project will become "a new standard of practice" around the country.