Democratic presidential candidate Bernie Sanders speaks in Des Moines, Iowa, last month. (Scott Olson/Getty Images)

Sen. Bernie Sanders (I-Vt.) will unveil a plan Thursday to ban privately run jails and prisons, which he says have a “perverse incentive” to increase the number of incarcerated people in the country.

Under the proposal by the Democratic presidential hopeful, the federal government would have three years to end its practice of using private companies to keep people behind bars. The ban would also apply to state and local governments, which have increasingly turned to private contractors in a bid to save money.

“It runs counter to the best interests of our country,” Sanders said in an interview Wednesday. “You should not be making a profit off of putting people in prison.”

Sanders’s “Justice Is Not For Sale Act,” which he plans to introduce as legislation in Congress, also includes several provisions intended to dramatically reduce the number of immigrants who are held in detention facilities while awaiting court hearings on their legal status.

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The release of Sanders’s plan comes as he seeks to broaden his appeal among African-American and Latino voters, two key constituencies in the Democratic nominating process for whom the issue of privately run prisons and detention facilities has emerged as a hot-button issue.

Sanders is scheduled to appear at a news conference Thursday on Capitol Hill to unveil the bill, which is being sponsored in the House by Rep. Raul Manuel Grijalva (D-Ariz.).

Hillary Rodham Clinton has also expressed concerns about privately run prisons on the campaign trail but has not put forward a plan regarding their use. Another Democratic presidential hopeful, former Maryland governor Martin O’Malley, included a provision to phase out privately run facilities in a broader criminal justice plan he recently released.

As a lawmaker, Sanders has not previously tackled the issue of privately run prisons, but he said it is consistent with his long-standing concern that the United States is locking up far too many people. On the campaign trail, he frequently describes the “international disgrace” that more people are incarcerated in the United States than any other country in the world.

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The bill Sanders will introduce includes another provision aimed at lowering the prison population: reinstating the federal parole system, which was abolished in 1984 as part of a wave of tough-on-crime legislation. Sanders said there needs to be flexibility in the system to release those who have been rehabilitated.

More than 19 percent of federal prisoners are housed in private facilities, as are nearly 7 percent of state prisoners, according to statistics cited by Sanders in a two-page summary of his legislation. Meanwhile, Immigration and Customs Enforcement holds more than 60 percent of its detainees in private facilities.

Among the immigration-related provisions in Sanders’s legislation is ending a congressional mandate that ICE maintains a minimum of 34,000 detainees a day.

“That seems pretty silly, and is obviously wrong,” Sanders said.

On the campaign trail, Clinton has at times spoken derisively of private prison companies, saying in June, for example, that it’s an industry “that makes money off of mass incarceration.” She has also accused the companies of cutting corners to boost their bottom line.

Clinton has also taken some grief in recent months because lobbyists for two of the largest private prison companies are helping raise money for her campaign.

Sanders said in the interview that he plans to continue his practice of using his position as a senator to highlight his agenda as a presidential candidate. While presidential candidates typically issue position papers, Sanders said putting his ideas in the form of legislation gives a fuller picture of where he wants to take the country.

Staff writer Anne Gearan contributed to this report.