New Jersey authorities seized nearly 40,000 "doses" of heroin and fentanyl as well as 22 firearms as part of two separate probes in Trenton and Paterson, the attorney general said Thursday.

Attorney General Gurbir Grewal spoke during a news conference, announcing that authorities arrested 38 people, including the head and founder of a Bloods-affiliated gang, as part of the long-term investigations.

"Our state is facing two public health crises," Grewal said. "We're facing an opioid epidemic, and we're facing an epidemic of gun violence."

All of the guns seized and 220 bricks of heroin — enough for 11,000 individual "doses" of the opioid — were seized in Trenton, according to the state's top law enforcement official. Five of the guns were assault rifles.

In Paterson, 27,000 waxed paper packets of the opioids were confiscated. Authorities referred to the individually wrapped packets as "doses."

Grewal said prosecutors are charging some of the defendants using a law enacted about year ago by the Democrat-led Legislature and Democratic Gov. Phil Murphy that lowered magazine capacities from 15 to 10.

Along with the guns and opioids, authorities seized $52,000 in cash.

The firearms seizure comes shortly after the weekend's fatal shootings in Texas and Ohio that left 31 people dead and just days after New Jersey officials signed a gun-violence intervention measure into law.

Grewal said it's unclear whether any of the guns the state seized have been used in crimes but that authorities are trying to determine if they were. He added that about four-fifths of New Jersey's so-called crime guns come from out of state.

Officials also arrested Kashard Whitaker, a founding member of the 4K Boyz Bloods gang.

Grewal says the probe disrupted two opioid mills and involved officials from local, state and federal law enforcement.

In a statement, Grewal's office said the arrests and seizures were carried out last week.

A woman who answered the phone at Whitaker's attorney's office said it had no comment.