Department of Homeland Security Secretary Kirstjen Nielsen announced from the White House briefing room on Wednesday that President Donald Trump is deploying National Guard troops to the U.S. southern border immediately in conjunction with the border state governors.

Nielsen told reporters that she was not going to get ahead of governors on the size and duration of the effort, but that “it will be strong. It will be as many [troops] as are needed to fill the gaps today.” She said the action would be similar to Operation Jumpstart under President George W. Bush.

She said they are looking at options to build a wall along the border where they place military installations.

Nielsen said that replacing current border wall counts as new wall.

She said they are seeing more advertising from smugglers and traffickers as well as pitches to “borrow” children to appear as family units that may give them a greater chance at being allowed to stay in the U.S.

DHS has watched for current and emerging threats and despite steps the Trump administration has thus far taken over the past 15 months, they are still seeing drugs and people smuggled across the border, said Nielsen, who marked it as a threat to children and rule of law.

“Border security is national security which is homeland security,” said Nielsen. “The threat is real.”

She pointed out that despite a 40 percent decrease in crossing last year, they have now seen crossing surge to prior levels.

Nielsen said that the operation will be overseen by the president and expressed the administration’s hope that Congress will finally act on loopholes in immigration law. She pointed out that smugglers are using claims of “credible fear” to get their human cargo into — and remain in — the United States. She also pointed out that these traffickers are taking advantage of loopholes that make it harder for the U.S. to remove individuals from Central American countries due to immigration law. The secretary said the issue has been exacerbated by the deeply flawed Flores agreement, a courtroom settlement which contributes to catch and release.

The secretary added that these false claims of “credible fear” are also making it harder to help those with valid claims.

The National Guard’s activities are expected to include countering criminal activity, aerial support, and some infrastructure construction where able, and aerial support. Nielsen confirmed that there may be some wall built by these troops where military installations are placed.

Nielsen added that counterparts in Mexico have been informed about this action and they understand and respect U.S. national sovereignty. She said the Trump administration does do not expect this operation to affect the U.S. relationship with Mexico and that Congress has the ability and opportunity to provide the country with what it needs for border security.

The secretary emphasized that the U.S. welcomes legal immigrants, that the president is committed to securing the border, and that this is not a partisan issue.