SAN FRANCISCO — California’s highway patrol and national guard will bring in additional people and resources to help San Francisco battle its worsening fentanyl drug crisis, Gov. Gavin Newsom announced Friday.

The announcement highlights a serious concern in the city where Newsom was once mayor. Overdose deaths have soared, and authorities have been unable to stop rampant open-air drug dealing and use.

Newsom said in a statement that the partnership will “crack down on crime linked to the fentanyl crisis” and hold “poison peddlers accountable.” The operation will not result in criminalizing people addicted to drugs, the statement said.

The news was welcomed by San Francisco Mayor London Breed, the district attorney’s office and the police chief, who have all vowed to get tough on large-scale drug traffickers.

The California Highway Patrol will assist in training and traffic enforcement while the California National Guard will help analyze drug trafficking operations with the aim of dismantling them, according to the statement.

Newsom made a surprise visit this week to the city’s Tenderloin and South of Market neighborhoods, which are rife with drug use and dealing.

Mayor Breed has repeatedly pledged to crack down on drug dealing in the Tenderloin, but conditions have not improved.