Reform groups are hoping a landmark settlement to effectively end indefinite solitary confinement in California state prisons will soon spread.

"There is still much work to be done to end solitary confinement both in California and around the nation," Jules Lobel, president of the Center for Constitutional Rights and the lead attorney representing inmates, said in a conference call with reporters Tuesday. "This settlement represents an important step in that direction and in the growing movement against solitary."

As the state that keeps inmates segregated for longer than any other, at times up to a decade or more, California's acceptance of the changes represents a significant victory in the broader push against solitude. The state has agreed to segregate only inmates who commit new crimes behind bars and will no longer lock gang members in soundproofed, windowless cells solely to keep them from directing illegal activities by gang members.

Corrections and Rehabilitation Secretary Jeffrey Beard told The Associated Press that the settlement will "move California more into the mainstream of what other states are doing while still allowing us the ability to deal with people who are presenting problems within our system."

The conditions triggered intermittent hunger strikes by tens of thousands of inmates throughout the prison system in recent years. Years-long segregation also drew criticism this summer from President Barack Obama and U.S. Supreme Court Justice Anthony Kennedy.

The lawsuit was initially filed in 2009 by two killers serving time in the security housing unit at Pelican Bay. By 2012, Todd Ashker and Danny Troxell were among 78 prisoners confined in Pelican Bay's isolation unit for more than 20 years, though Troxell has since been moved to another prison.

More than 500 had been in the unit for more than 10 years, though recent policy changes reduced that to 62 inmates isolated for a decade or longer as of late July.

The suit contended that isolating inmates in 80-square-foot cells for all but about 90 minutes each day amounts to cruel and unusual punishment.

About half the nearly 3,000 inmates held in such units are in solitary confinement, while the rest are held with at least one other inmate.

Inmates have no physical contact with visitors and are allowed only limited reading materials and communications with the outside world.

The settlement will limit how long inmates can spend in isolation, while creating restrictive custody units for inmates who refuse to participate in rehabilitation programs or keep breaking prison rules.

They will also house those who might be in danger if they live with other inmates.

Beard said he will work to ease the unions' previously expressed concerns that guards could face additional danger. He said the settlement expands on recent changes that have reduced the number of segregated inmates statewide from 4,153 in January 2012 to 2,858 currently.