Cooper called the shooting a "senseless act of violence" and that flags be lowered to honor the lives lost and in solidarity with the mourning families.
"Governor Roy Cooper has ordered all United States and North Carolina flags at state facilities to be lowered immediately to half-staff until sunset on Sunday, May 30, 2021 honoring the victims of the tragedy in San Jose, California who lost their lives today to a senseless act of violence," the order wrote. "In tribute to the lives lost and the families in mourning all North Carolinians are encouraged to join in lowering flags to half-staff in their honor."
Nine people in total were killed, including the shooter, at a light-rail facility for the Valley Transportation Authority. A man wounded in the shooting is in critical condition at a local hospital, according to a spokesperson.
The incident is one of the latest mass killings as the nation emerges from coronavirus restrictions.
At the White House, President Joe Biden also ordered flags to be flown at half-staff and urged Congress to act on legislation to curb gun violence.
"Every life that is taken by a bullet pierces the soul of our nation. We can, and we must, do more," Biden said in a statement.
The Associated Press contributed to this report.