Former First Lady Laura Bush has spoken out against the Trump administration's policy that sees migrant families separated at the border.

In an op-ed piece for the Washington Post she called the 'zero tolerance' policy 'cruel' and 'immoral', as public outcry begins to grow over the hundreds of children that are currently being held in detention centers.

'I live in a border state. I appreciate the need to enforce and protect our international boundaries, but this zero-tolerance policy is cruel. It is immoral. And it breaks my heart,' the former First Lady wrote.

'Our government should not be in the business of warehousing children in converted box stores or making plans to place them in tent cities in the desert outside of El Paso.'

Former First Lady Laura Bush attacked the Trump administration's policy that has led to nearly 2,000 immigrant children being separated from their parents

The Bushes have steered clear of politics since their departure from the White House in 2008

Occupants at Casa Padre, an immigrant shelter for unaccompanied minors, in Brownsville, Texas, U.S., are seen in this photo provided by the U.S. Department of Health

Her commentary comes as a number of images and accounts from inside the detention centers have emerged.

Reports about the centers described children being kept in 'cages' after being separated from their parents, who crossed the border illegally.

The Department of Homeland Security reports that nearly 2,000 children were sent to mass detention centers between April 19 and May 31.

Bush wrote how the camps were 'eerily reminiscent' to those set up to hold Japanese Americans during World War II.

'Americans pride ourselves on being a moral nation, on being the nation that sends humanitarian relief to places devastated by natural disasters or famine or war,' she wrote. 'We pride ourselves on believing that people should be seen for the content of their character, not the color of their skin. We pride ourselves on acceptance. If we are truly that country, then it is our obligation to reunite these detained children with their parents — and to stop separating parents and children in the first place.'

Heartbreaking photos released Sunday showed inside of a processing center

It is unprecedented for a former First Lady to criticize the policies of a current president

She also invoked the name and memory of her mother-in-law, former first lady Barbara Bush, who died in April.

Barbara Bush was also an advocate for children while her husband, George H.W. Bush, was in office. In one particularly memorable moment during her tenure almost three decades ago, Barbara Bush spent time with babies who had HIV/AIDS, picking them up and holding them.

'My mother-in-law never viewed her embrace of that fragile child as courageous. She simply saw it as the right thing to do in a world that can be arbitrary, unkind and even cruel,' writes Bush. 'She, who after the death of her 3-year-old daughter knew what it was to lose a child, believed that every child is deserving of human kindness, compassion and love.

It's a rare public admonishment of current administration policy from Bush, who has rarely weighed in on politics since her husband left office.

Japanese-Americans were evacuated from certain West Coast areas under US Army War Emergency Order in 1942. Laura Bush is likening the current camps to this traumatic event

Japanese encampment was started by U.S. during World War II. IN this photo, Japanese- U.S. citizens are seen being checked in to internment camp, a measure which later proved illegal

The McAllen facility is reportedly where more kids are separated from their parents than anywhere else in the US

Attorney General Jeff Session announced the zero tolerance policy earlier this year stating how the Justice Department would prosecute all adults crossing the border illegally, which could result in families being separated.

Homeland Security chief Kirstjen Nielsen defended the administration in a series of tweets on Sunday, claiming that the administration does not have a policy of separating families at the border.

Just hours before Bush's piece was published, current First Lady Melania Trump's communications director Stephanie Grisham told CNN, 'Mrs. Trump hates to see children separated from their families and hopes both sides of the aisle can finally come together to achieve successful immigration reform. She believes we need to be a country that follows all laws, but also a country that governs with heart.'

Children were seen lying on green mats with foil sheets intended to serve as blankets. This heartbreaking photo shows the children at a Border Patrol processing facility in McAllen, Texas

Hundreds of children were seen waiting in cages created by metal fencing

Homeland Security chief Kirstjen Nielsen defended the administration in a series of tweets on Sunday, claiming that the administration does not have a policy of separating families

President Trump has repeatedly blamed congressional Democrats for not acting on immigration and doing more to strengthen border security. Other members of the administration, however, have defended the policy as a necessary border security measure.

Trump has pointed to a 2008 anti-trafficking law passed by President George W. Bush, although there is no federal law requiring family separation.

In her op-ed, Bush called for 'good people at all levels of government' to address the problem.

'In 2018, can we not as a nation find a kinder, more compassionate and more moral answer to this current crisis?' she wrote. 'I, for one, believe we can.'