The Trump administration is sending the National Guard to the southern border, per a presidential memorandum issued on Wednesday. Citing a “drastic surge of illegal activity on the southern border” including drug trafficking, illegal border crossings, and gang activity, President Trump authorized the Defense and Homeland Security departments to deploy and use National Guard personnel to stop this activity. The memo also requests a report within 30 days that contains “findings and an action plan” for securing the border.

When will this all take place? Homeland Security secretary Kirstjen Nielsen told reporters at the White House on Wednesday that “we do hope that the deployment begins immediately” but was unable to give details, nor could she say how many guardsman would be deployed and for how long. “It will be strong. It will be as many as is needed to fill the gaps that we have today, is what I can tell you,” Nielsen said.