Chelsea Clinton said Senator Bernie Sanders’ proposal to end mass incarceration in the US is "worrying" and insinuated that her mother’s rival does not understand what is “possible” to achieve in Government.

Speaking to a packed town hall in Cleveland, Ohio, Chelsea Clinton took the opportunity to denounce Senator Sanders’ proposed criminal justice reforms when she was asked about her mother’s “vagaries” towards African American policy.

She replied that Senator Sanders advocated the end of mass incarceration, aiming for the US to no longer be the country with the highest number of people in jail by the end of his first term in 2020 - but his plan "worried" her.

The US currently has 2.2 million people behind bars, 600,000 more people than China.

Chelsea Clinton said the goal was not achievable, however, as the majority of inmates are held at state, not federal, prisons.

“We are not electing a king, we are electing a president,” insisted Ms Clinton. “We need someone who understands what they have to do in the job [as president] but also in partnership with congress, governors and mayors.”

“My mother understands how the government works,” she added.

Her comments come amid a growing perception that Hillary Clinton's policies are too moderate while Bernie Sanders' proposals might be more pie-in-the-sky.

In pictures: Hillary Clinton's 2016 presidential bid Show all 30 1 /30 In pictures: Hillary Clinton's 2016 presidential bid In pictures: Hillary Clinton's 2016 presidential bid Clinton campaign 11/09/2016: Hillary Clinton waves to the press as she leaves her daughter's apartment building after resting in New York. 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Senator Sanders proposes abolishing prisons for profit, which have an incentive to lock up more people, to legalize marijuana, and to eliminate “mandatory minimums” for drug-related crimes which result in sentencing disparities between black and white people.

But Ms Clinton's daughter argued that reform needs to come in the shape of education and the promise of jobs, citing her mother’s “cradle to education and cradle to jobs pipeline” policy for historically disenfranchised communities like inner cities and rural areas.

At the Democrat debate last week, Hillary Clinton accused Senator Sanders of “abandoning” president Barack Obama and openly criticised him as she aimed to shore up support among African American voters.

Senator Sanders in turn made frequent references to the high number of African Americans who are in prison.

Erica Garner joins Bernie Sanders campaign video