Attorney General Jeff Sessions argued the US wouldn't face the "terrible choice" of separating children from their families if there was a border wall.
"Congresswoman Jenkins does not support forcibly separating children and their parents and believes the practice, which is not new to this Administration but has increased in volume under it, has gone on long enough", her office said in a statement.
"The notion that the government should intrude into the rights of a parent to be with their child has historically been met with extremely high levels of scrutiny", the letter reads. "I ask that you take immediate action to end the practice of separating children from families at the border".
"We do have a policy of prosecuting adults who flout our laws to come here illegally instead of waiting their turn, claiming asylum at ports of entry". "As former United States Attorneys, we also emphasize that the Zero Tolerance policy is a radical departure from previous Justice Department policy, and that it is unsafe, expensive, and inconsistent with the values of the institution in which we served", they wrote in the letter posted online Tuesday.
The US government has separated at least 2,000 children from parents at the border since implementing a policy that results in such family separations, the Department of Homeland Security confirmed Friday.
"But as former United States Attorneys, we also emphasize that the Zero Tolerance policy is a radical departure from previous Justice Department policy, and that it is unsafe, expensive, and inconsistent with the values of the institution in which we served", they wrote.
That might sound like a white supremacist remark, and critics have certainly pilloried Trump, Sessions and others in the president's administration for comments and policies deemed insensitive if not outright hostile to racial minorities.
Democratic attorneys general are demanding the Trump administration end a "zero tolerance" policy that has resulted in children being separated from their parents at the U.S. -Mexico border.
The policy places adults trying to cross the border into custody, and places children in detention centres. They said that while the crisis of family separation cases has multiple causes, the immediate cause is the administration's "zero-tolerance" policy.
Both Republican and Democratic former USA attorneys argue that the policy goes beyond "inhumane" - it overburdens the justice system by requiring a surge in resources to handle cases that are Class B misdemeanors.
But Trump and his allies have seized on the report to try to undermine the validity of Mueller's probe, arguing it showed key law enforcement officials were biased against him.
Almost 2,000 children were separated from their families over a six-week period in April and May after Sessions announced the new "zero-tolerance" policy that refers all cases of illegal entry for criminal prosecution. "We can not and will not encourage people to bring children by giving them blanket immunity from our laws". The figures are for people who tried to enter the USA between official border crossings.