(CNN) In a major education policy speech set to be delivered Saturday, Sen. Bernie Sanders will call for a ban on all for-profit charter schools, a position that puts him directly at odds with the Trump administration and becoming the first of the 2020 Democratic presidential candidates to insist on such a move.

The Vermont independent also will call for a moratorium on the funding of all public charter school expansion until a national audit on the schools has been completed. Additionally, Sanders will promise to halt the use of public funds to underwrite all new charter schools if he is elected president.

A senior Sanders campaign official shared the details of policy proposal with CNN ahead of the Sanders speech in South Carolina -- the crucial early primary state where the African-American vote is a key voting base. The moratorium on the funding of public charter schools was initially called for by the NAACP; Sanders will say in his speech that he supports the group's efforts.

Sanders will also make the case that the growth of charter schools has done disproportionate harm to the black community because it has pulled public dollars away from community public schools.

He will give his speech in Orangeburg on the anniversary weekend of the historic Brown v. Board of Education Supreme Court decision that ruled that segregation in public schools was unconstitutional.

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