NEW BEDFORD - In what officials said was the largest drug sweep conducted in southeastern Massachusetts, 44 people were arrested in New Bedford on federal and state drug charges today. Many of the arrested are alleged to be leaders or associates of the Latin Kings street gang, law enforcement officials said.

Over the course of an 18-month investigation, the individuals arrested Friday sold narcotics to undercover police officers and cooperating witnesses in New Bedford, according to the office of US Attorney Carmen M. Ortiz.

“The neighborhoods are safer now than they were mere hours ago,” Richard DesLauriers, special agent in charge of the FBI’s Boston office, told reporters. The investigation was conducted by the FBI and the Southeastern Massachusetts Gang Task Force.

At the press conference, New Bedford Mayor Jonathan F. Mitchell promised arrests like these would be a recurring event until the city is safe.

“New Bedford isn’t open to this type of business,” he said.

In 2006, a similar investigation led to the prosecution of 37 Latin Kings members and associates, “significantly disrupting the gang for several years,” Ortiz’s office said. In 2010, officials began to see an increase in violence and street-level drug sales in areas of New Bedford known to be occupied by the Latin Kings, Ortiz’s office said.

Of those arrested this morning, 16 are facing federal narcotics violations, 26 face state narcotics violations, and two were charged by criminal complaint, according to officials. Two individuals have been charged, but remain at large, authorities said. The ages of those arrested range from 16 to 53 years old. With the exception of two, all suspects are residents of New Bedford.