WASHINGTON (CBSNewYork/AP) — The Mexican foreign ministry says U.S. Homeland Security Secretary Kirstjen Nielsen has told Mexico’s top diplomat that U.S. National Guard troops being deployed to the border “will not carry arms or carry out migration or customs control activities.”

Mexican Foreign Secretary Luis Videgaray is in Washington on a visit. A foreign ministry statement issued Wednesday night says Nielsen told Videgaray that the troops will only be providing support for Department of Homeland Security work.

It says the deployment will be similar to ones in 2006 under President George Bush and in 2010 with President Barack Obama.

President Donald Trump signed a proclamation Wednesday directing the National Guard to be deployed to the U.S.-Mexico border.

Trump said Wednesday in a memorandum to his secretaries of defense and homeland security and to his attorney general that the “situation at the border has now reached a point of crisis.”

The document orders the Secretary of Defense to support the Department of Homeland Security in securing the southern border to stop the flow of drugs and people. And it orders the agency heads to submit a report within 30 days outlining what other steps can be taken.

Trump said that “lawlessness” at the southern border is “fundamentally incompatible with the safety, security, and sovereignty of the American people.” And he said his administration “has no choice but to act.”

At the White House on Wednesday, Nielsen couldn’t describe the size of the force, the estimated cost or the duration, CBS News reported.

“I don’t want to get ahead of the governors,” she said. “This is a partnership with them. As soon as the numbers are available we’ll provide that.”

In a statement Wednesday, Arizona Gov. Doug Ducey said he looks forward to working closely with federal officials on the issue.

(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)