Former first lady Laura Bush says the policy of separating immigrant parents and children along the nation's southern border is "cruel," ''immoral" and "it breaks my heart."

Bush was writing a guest column for The Washington Post Sunday and compared the policy to the internment of Japanese Americans during World War II.

"I appreciate the need to enforce and protect our international boundaries, but this zero-tolerance policy is cruel," she wrote.

She said "the U.S. 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."

She said it was "eerily reminiscent of the Japanese American internment camps of World War II," which she said are "now considered to have been one of the most shameful episodes in U.S. history."