“We expect this to problem to continue and there is no short-term solution in sight," said Osorio Chong during a visit to a refugee camp in Mexicali.
527,127 people who were supposed to leave the U.S. in the 2015 fiscal year overstayed, according to the Homeland Security Department
Alfonso Aguilar, who recently organized a support letter on behalf of Trump, said he felt "disappointed and misled" by the fiery speech and withdrew his backing.
The Republican presidential nominee vowed on Wednesday that anyone who is in the United States illegally would be subject to deportation if he is elected.
Trump's new language seemed to reveal an awareness that his unyielding stance against immigrants is unlikely to get him to the White House, with Latinos voting in growing numbers in key states.
Trump escalated his attacks on U.S. District Judge Gonzalo Curiel, the son of Mexican immigrants who is the presiding judge in lawsuits involving fraud allegations against Trump University, the New York businessman's defunct real estate training school.