WASHINGTON -- President Trump sent two members of his Cabinet south of the border on Wednesday, to explain his new crackdown on illegal immigration.

The fence-mending mission began with Secretary of State Rex Tillerson’s arrival in Mexico City for a meeting with Mexico’s president.

Earlier, Homeland Security Chief John Kelly assured Guatemala’s leader that Mr. Trump is not interested in mass deportation.

“He (Trump) has given me -- emphasized the mission of intercepting irregular immigrants from any country on our border, treat them humanely and return them to their country of origin as fast as possible,” Kelly said.

Homeland Security Chief John Kelly assured Guatemala’s leader that President Trump is not interested in mass deportation. CBS Evening News

But the topic of fence-building is still a sore subject.

Mexico’s foreign minister said on Wednesday he’d take the fight to the U.N. to defend the rights of immigrants in the U.S.

Mr. Trump’s new immigration order could subject millions of people living in the U.S. illegally to deportation back to Mexico -- even if they’re originally from a third country. It prioritizes anyone convicted of a crime or charged with an offense.

The policy is deeply unpopular in Mexico, as is the wall that Mr. Trump has vowed to build along the 2,000-mile shared border.

On Wednesday, House Speaker Paul Ryan’s office released a picture of him touring the border area.

White House Spokesman Sean Spicer downplayed the tension, calling relations with Mexico “phenomenal.”

White House Spokesman Sean Spicer downplayed the tension, calling relations with Mexico “phenomenal.” CBS Evening News

“Secretary Tillerson and Secretary Kelly are going to have a great discussion down there and to walk through the implementation of the executive order,” Spicer said.

This is the first high stakes trip for Tillerson who has largely been silent during his almost three weeks on the job. State Department officials insist that he is in close contact with the president and point out that they met earlier today.