A Massachusetts man pleaded guilty in Maine on Wednesday to sex trafficking charges, admitting that he employed drugs and threats to force two women to engage in prostitution.

Rashad Sabree, 37, of Boston, pleaded guilty in U.S. District Court to two counts of sex trafficking by force, fraud or coercion, federal officials said.

According to court documents, Sabree coerced two young women to engage in sex acts for pay in Maine for two months, beginning in December 2015.

Authorities said he used the women’s heroin addictions, verbal abuse and threats of violence to control them and force them into commercial sex. Sabree gave them small amounts of heroin to avoid withdrawal symptoms and then threatened to stop supplying the drug if they wouldn’t engage in sex with paying customers.

Sabree was arrested on Jan. 5, 2016, when a motorist on Interstate 95 called 911 to report seeing a man hit a woman while headed south on the highway.

The arrest and prosecution of Sabree was part of an initiative of the departments of Justice, Homeland Security and Labor targeting sex trafficking.

Maine is one of six nationwide districts operating the program, which includes special anti-trafficking teams focused on cases of forced labor or sex trafficking.

Under a plea agreement, Sabree faces a sentence of 15 to 17 years, a fine of up to $250,000 and mandatory restitution to the victims.

Sentencing will be at a later date.