Updated at 11:34 p.m.

The Trump administration deployed approximately 500 National Guard troops to the U.S.-Mexico border late Friday, the Departments of Defense and Homeland Security announced after 10 p.m. ET Friday.

"Tonight, National Guard troops are deploying to support border security missions along the U.S. southwest border," Defense Secretary Jim Mattis and Homeland Security Kirstjen Nielsen said in a joint statement.

"Working closely with the border governors, the Department of Homeland Security identified security vulnerabilities that could be addressed by the National Guard. We appreciate the governors' support and are dedicated to working with them to secure the national borders," they added.

The two Cabinet members said the decision to send troops down to the Southwest border was part of the administration's commitment to use "every lever of power" to support Customs and Border Protection, as well as Border Patrol and local law enforcement following reports last weekend that a 1,000-person caravan of Central American migrants were traveling to the U.S.

National Guard Chief Gen. Joseph Lengyel said 500 troops — along with vehicles, helicopters, and equipment — are en route to the border.



Always Ready, Always There! Moving up to 500 #NationalGuard troops immediately on the SW border security mission. Vehicles, equipment & helicopters on the way tonight. https://t.co/nIjKEY5SSv — Gen. Joseph Lengyel (@ChiefNGB) April 7, 2018



The Texas National Guard posted video online of Lakota aircraft departing for the mission.



#Texas #NationalGuard Lakota aircraft currently on their way to the US -Mexico border. pic.twitter.com/kFnlNnNBtx — Texas Military Dept (@TXMilitary) April 7, 2018



Republican Govs. Greg Abbott of Texas and Doug Ducey of Arizona announced earlier Friday evening plans to send National Guard members to the border over the next week.

Abbott said 250 troops would head out by Monday evening at the latest.

Ducey said around 150 members would ship out sometime next week.

New Mexico Gov. Susana Martinez has not indicated whether she will support Trump's plan to supplement law enforcement, which he proposed Wednesday due to Congress's refusal to fully fund his $25 billion wall and a recent major uptick in illegal immigrant apprehensions last month.

California Gov. Jerry Brown has said he will not cooperate with the Trump administration.

The administration could send thousands of troops to help CBP and Border Patrol. Mattis approved a plan for 4,000 guardsmen and airmen earlier Friday.

On Thursday, Trump had told reporters he envisioned 2,000 to 4,000 service members being deployed.

Trump's reaction to the recent increase in the number of migrants apprehended while attempting to illegally enter the U.S. is not unprecedented.

During spikes in Presidents George W. Bush and Barack Obama's administrations, both ordered 6,000 guardsmen and 1,200 guardsmen to the border, respectively.