PORTLAND – Maine crime grew 4.6 percent last year for the biggest one-year increase in more than a decade, and drugs were fueling the trend, the Maine Department of Public Safety reported Wednesday.

Public Safety Commissioner Anne Jordan blamed drugs for an 18.6 percent jump in robberies, marking the second year of double-digit growth. There also was a 7.9 percent increase in burglaries and a 4.2 percent increase in thefts.

“Most of the robberies, burglaries and thefts during the past year are a direct result of feeding Maine’s drug habit,” Jordan said.

The increase in crime marks a turnaround following several years of decline. Last year, there was a slight increase of 0.4 percent in crime but that followed a three-year drop in which crime fell 4.1 percent in the state, officials said.

The trend affected rural and urban communities alike.

Cities and towns with full-time police departments saw a crime increase of 1.3 percent and rural areas served by deputy sheriffs and state troopers saw an increase of 1.9 percent, according to the Department of Public Safety.

The number of homicides was close to Maine’s historic average but nine of Maine’s 23 homicides, or 39 percent, were classified as domestic, continuing a trend that has vexed law enforcement and domestic violence activists.

Domestic violence assaults also increased by 1.7 percent and reported sexual assaults grew by 5.6 percent, the department said.

Among other crimes, arson grew 9 percent. Crimes that showed decreases were aggravated assault, which dropped 5.6 percent, simple assault, which fell 1.1 percent, and motor vehicle theft, which declined 0.3 percent.

Overall, the 4.6 percent increase in crime was the biggest since 1993, when crime grew 3.6 percent, said Stephen McCausland, spokesman for the Maine Department of Public Safety.

Roy McKinney, director of the Maine Drug Enforcement Agency, said there’s no doubt that drugs are the primary cause for the crime increase, and he said budget cuts are hampering drug agents’ ability to stay ahead of traffickers.

Drugs, guns and gangs are blamed on an uptick in crime across the nation, and the trend holds true in Maine, McKinney said.

Gangs in southern New England have discovered that Maine is profitable because there’s less law enforcement and higher profits, McKinney said. A bag of heroin costs $10 or less in Boston, but it sells for $30 in Maine, he noted.

There were 82 drug arrests two weeks ago in Maine, and there have been significant drug seizures in recent days on the Maine Turnpike, including 1.4 pounds of cocaine based on a tip and $25,000 worth of heroin following a crash, officials said.

The growing drug problems come at a time of reduced funding for drug enforcement and fewer state troopers patrolling the state’s roads, and there’s an effort afoot to divert money from the state police to the Transportation Department, Jordan said.

“People in Maine are going to have to make some tough decisions,” she said. “What kind of public protection do they want in this state?”

The figures on eight categories of crime are tabulated each year by the Department of Public Safety’s Uniform Crime Reporting Division and are based on reports from local, county and state law enforcement agencies.

The 34,996 index offenses in 2006 represent a crime rate of 26.5 offenses per 1,000 people in Maine, compared to the national average of 41.15 offenses per 1,000 people in 2005. Maine’s 2005 crime rate was 25.36 per 1,000.