BURLINGTON (AP) -- Vermont is making headway in its battle against heroin and other illegal drugs, law enforcement officials say.

Since federal prosecutors announced six months ago that combating heroin and other opiates would be a top priority, authorities have arrested several alleged "upper-level traffickers," said U.S. Attorney for Vermont Tristram Coffin.

The number of typically drug-related crimes such as assaults, larcenies and robberies have been dropping in 2013 after years or increasing, said Burlington Police Chief Michael Schirling.

"We are making some significant progress," Schirling told the Burlington Free Press (http://bfpne.ws/1ccOqai). "We’ve had some significant cases not just here, but on a parallel basis in places like Rutland and St. Albans."

Just last month a Chicago man accused of being the ninth member of a drug ring that is thought to have sold large amounts of a strong form of heroin in the state was arraigned in Burlington.

Bunthan Sam is being held pending trial after pleading not guilty to drug-trafficking. Court papers accuse him of being "one of the principal out-of-state suppliers" of a strong type of heroin called "Chi-town" that has been linked to a number of overdoses in the Burlington area.

Police also arrested Edwin Biggs of Brooklyn, N.Y., and two others after finding 2,900 bags of heroin and $26,000 in cash in their hotel room in South Burlington, a police affidavit said. The three have pleaded not guilty.

"We have made progress in dismantling some of the distribution networks that have operated in this state. But there’s always more work to done," Coffin said.

Drug treatment also is showing progress. Five regional substance abuse treatment centers for addicts are expected to be set up by January. One has opened at the HowardCenter in Burlington. The center evaluates clients’ needs, provides methadone and buprenorphine medications and develops treatment plans. Another center is expected to open in Rutland soon this year.