Trump sending National Guard to southern border

President Trump will sign a proclamation today that immediately deploys National Guard troops to secure the southern border with Mexico, according to Homeland Security Secretary Kirstjen Nielsen.

Nielsen said the White House would coordinate with state governors and the Defense Department. She said she was unable to provide further details on the size, cost or timeline of the effort because it had only just begun.

"We hope to have the path forward very much specified in the near future," she said.

Nielsen also said DOD was considering building walls at military installations near the border. She added that Trump has been "frustrated" by Congress thus far in his effort to build a wall on the southern border.

DOD did not respond to a request for comment.

Nielsen said the administration does not yet know the cost of the deployment, but compared it to Operation Jump Start under former President George W. Bush, which cost $1.6 billion and involved approximately 6,000 guard troops.

Two White House officials said during a phone call with reporters that final plans were still in development regarding the role of National Guard troops.

The officials said troops could be deployed to the border "very quickly."