Dominican drug trafficking gangs dominate the balance of heroin distribution in Boston, according to a new report from the Boston Police Department.

The Boston Regional Intelligence Center (BRIC), a Boston Police division that also receives funding from the Department of Homeland Security (DHS), released the “2016 Heroin Overdose Report” Tuesday to provide data on trends in opiate use in the city.

An analysis of arrest data for Class A drug trafficking — selling heroin, morphine and synthetic opioids — revealed the majority of individuals arrested in 2016 in Boston were not U.S. citizens, and most of those non-citizens were Dominican foreign nationals.

Of those arrested for Class A trafficking, 65 percent claimed to have been born in a foreign county. Within that group, 84 percent told police they were from the Dominican Republic. The share of heroin trafficking arrests attributable to Dominican nationals is likely even higher, the BRIC report says, because illegal immigrants from the Dominican Republic often use fake Puerto Rican birth certificates to obtain state identification documents.

“There has been open source reporting that Dominican drug traffickers will use identities stolen from Puerto Rico to acquire drivers licenses in Massachusetts, and in other states,” the report said.

Identity fraud exploiting Puerto Rican nationality is a major facilitator of heroin distribution in Boston, according to the BRIC report. In particular, Dominican nationals were suspected of using Puerto Rican identity documents or aliases to mask their true country of origin and lack of legal status in the U.S.

“In 59 percent of the cases where the suspect listed Puerto Rico as their place of birth, there were signs of identity fraud or use of aliases. This would suggest that heroin trafficking in Boston is largely controlled by Dominican drug organizations,” the report concluded.

Overall, signs of identify fraud were present in 44 percent of all arrests in 2015 and 2016 when the suspect listed a place of birth other than the U.S.

Massachusetts Republican Gov. Charlie Baker and Boston Mayor Marty Walsh have both launched efforts to combat opioid abuse and addiction, but they have resisted the Trump administration’s strict enforcement of immigration laws and expanded detention and removal of illegal aliens.

Boston was one of five Massachusetts cities DHS singled out in March for not honoring federal immigration detention requests, and Walsh has previously pledged to house illegal immigrants in Boston City Hall to shield them from federal agents.

He also lauded a California judge’s decision in April that temporarily halted President Donald Trump’s executive order to withhold funding from sanctuary jurisdictions, claiming that such cities “have the Constitution on our side.”

“In Boston, there is no dollar amount that would ever change our essential character of inclusiveness of all people,” Walsh said.