June 25 (UPI) -- More than 200 civil-rights groups are urging California Gov. Gavin Newsom to use his constitutional powers to commute more than 500 state death sentences.

"California's death penalty system is not only broken, it is deeply racist and unconstitutional," Michael Mendoza, national criminal justice director of the New York-based justice advocacy group LatinoJustice PRLDEF, said Wednesday in a statement.

The call arrives as some point to what they call an "overwhelming" amount of evidence of racial bias in how the death penalty is carried out in the state. Numerous civil rights orgs argue the death penalty is unconstitutional under the state Constitution's Equal Protection guarantees.

On Thursday, scores of advocates and national civil rights leaders will gather at the state's capitol building in Sacramento to visit Newsom and deliver a signed statement by nearly 200 organizations which implores the two-term Democratic governor to grant universal clemency to all of California's 574 inmates waiting on death row.

A public rally will start around 10:30 a.m. local time on the west steps of the capitol complex with a press conference to follow lead by leaders of renowned organized state and national groups like Clemency California coalition, the American Civil Liberties Union, National Center for LGBTQ Rights, Disability Rights California, Equal Justice Society, Chinese for Affirmative Action, the Ella Baker Center for Human Rights and several others.