SACRAMENTO, Calif. >> California Gov. Gavin Newsom is halting the execution of more than 700 condemned inmates on the nation’s largest death row Wednesday, for at least as long as he’s governor.

He will issue an executive order granting a reprieve to each one of the state’s 737 condemned inmates, his office told The Associated Press.

He’s also withdrawing the lethal injection regulations that death penalty opponents have already tied up in court. And he’s shuttering the new execution chamber at San Quentin State Prison that has never been used.

California hasn’t executed anyone since 2006, under then-Republican Gov. Arnold Schwarzenegger, and inmates are far more likely to die of old age.

Since then, the death row population has grown to house one of every four condemned inmates in the United States. They include Richard Davis, who kidnapped 12-year-old Polly Klaas during a slumber party and strangled her, and Lonnie Franklin Jr., convicted of killing nine women and a teenage girl in Los Angeles. He’s known as the “Grim Sleeper” because detectives thought he took a 14-year break in killing between 1988 and 2002.

The state’s voters have narrowly supported the death penalty, most recently in 2016 when they voted to speed up the process.

Newsom’s office said he can act unilaterally because he’s enacting a moratorium, not changing anyone’s sentence. He’s not commuting any death sentences, which in many cases would require agreement from the state Supreme Court. A governor needs approval from the state Supreme Court to pardon or commute the sentence of anyone twice convicted of a felony, and the justices last year blocked several clemency requests by former Gov. Jerry Brown.

While the governor’s move is certain to be challenged in court, aides cite his power to grant reprieves written into the state Constitution.

“I do not believe that a civilized society can claim to be a leader in the world as long as its government continues to sanction the premeditated and discriminatory execution of its people,” Newsom said in prepared remarks. “In short, the death penalty is inconsistent with our bedrock values and strikes at the very heart of what it means to be a Californian.”

He called the death penalty “a failure” that “has discriminated against defendants who are mentally ill, black and brown, or can’t afford expensive legal representation.”

He also argues that it doesn’t act as a deterrent, wastes taxpayer dollars and is flawed because it is “irreversible and irreparable in the event of human error.” California has spent $5 billion since 1978 on its death row, he said.

“The intentional killing of another person is wrong,” he said, “and as governor, I will not oversee the execution of any individual.”

His office said more than six in 10 condemned California inmates are minorities, citing racial disparities in who is sentenced to die. And it said five condemned California inmates were eventually exonerated since 1973.

California is the sixth state where a governor has enacted a moratorium. Republican Illinois Gov. George Ryan was the first to do so in 2000, though Illinois has since abolished the death penalty.

The governors of Pennsylvania, Washington and Oregon have imposed moratoriums on executions, and the former Colorado governor refused to execute someone on death row. The state’s new governor supports a repeal bill in the Legislature.

Newsom, a Democrat, told reporters earlier this month that he “never believed in the death penalty from a moral perspective,” also citing ethical and economic concerns. He said he’s campaigned “vigorously” for the last two ballot measures where voters rejected repealing the death penalty.

“The disparities are very real and raw to me now especially as I spend every week working on the issues of paroles and commutations,” he said.

Newsom cited one offender serving a sentence of 57 years-to-life for injuring three people, while another offender was sentenced to 17 years-to-life for a double murder: “One happened to be of one race, one happened to be another race. Other people I’ve seen literally put to death for lesser crimes, and that concerns me.”

Former Democratic Gov. Brown also opposed the death penalty, but his administration moved to restart executions after voters acted in 2016 to allow the use of a single lethal injection and speed up appeals. His administration’s regulations are stalled by challenges in both state and federal court, though those lawsuits may be halted now that Newsom is officially withdrawing them.

Brown said he was satisfied with his record number of pardons and commutations, though he never attempted to commute a death sentence, and with his sweeping changes that eased criminal penalties while reducing the prison population.

“I’ve done what I want to do,” Brown said shortly before leaving office, defending his decision not to endorse death penalty repeal efforts in 2012 and 2016. “I’ve carved out my piece of all this.”

Democratic Assemblyman Marc Levine of Greenbrae plans to seek the two-thirds vote the Legislature requires to put another repeal measure on the 2020 ballot. Levine’s district includes San Quentin State Prison, which houses California’s death row and execution chamber.

Newsom’s aides said it has not yet been decided what will become of the execution chamber, nor whether corrections officials have been told to top preparing for executions, for instance by running drills.

Seventy-nine condemned California inmates have died of natural causes since California reinstated capital punishment in 1978. Another 26 committed suicide. California has executed 13 inmates, while two were executed in other states.

Newsom’s office said 25 condemned inmates have exhausted all of their appeals and could soon have faced execution if the courts approved the state’s new lethal injection method.