The Pentagon has decided the thousands of troops who have been deployed to the U.S.-Mexico border will receive medals for their service.

Active duty, reserve, and National Guard members sent to the region after April 2018 will be eligible for the Armed Forces Service Medal, which was previously awarded to troops supporting border operations between 2006 and 2008.

"The Under Secretary of Defense has authorized the Armed Forces Service Medal to service members who have provided support to CBP, starting from April 7, 2018," said Pentagon spokesman Army Lt. Col. Chris Mitchell. The end date has not been determined since the operation remains in force. About 6,100 troops are stationed on the border, with regular rotations in and out.

To be eligible, troops must have served within 115 miles of the border in Texas, New Mexico, California, or Arizona. Members at sea who served within 24 nautical miles of the coast and those stationed at the mission headquarters in San Antonio are also eligible.

The Armed Forces Service Medal is given to troops who "participate, or have participated, as members of U.S. military units, in a U.S. military operation that is deemed to be a significant activity; and encounter no foreign armed opposition or imminent threat of hostile action," according to federal code.

President Bill Clinton established the medal by executive order in 1996. It has since been awarded for various peacekeeping, humanitarian, and support operations. The George W. Bush administration authorized the medal for troops aiding the Department of Homeland Security with "securing the southwest U.S. border" during Operation Jump Start between 2006 and 2008. More recently, it was awarded to troops who helped with Ebola relief operations in sub-Saharan Africa between September 2014 and June 2015 and those deployed to the U.S. Embassy in South Sudan with Operation Oaken Steel as violence broke out in the country from July 2016 to January 2017.

Retired Army Lt. Gen. Thomas Spoehr told the Washington Examiner the Pentagon's decision "is in keeping with the purpose of the award."

"It is a low-cost way to recognize the sacrifice of the service members deployed away from home, probably in hot and inhospitable conditions," Spoehr said. "Young troopers especially appreciate getting an award."

President Trump announced troop deployments to the border in April 2018, citing a crisis at the border after officials were overwhelmed by the number of Central American migrants fleeing violence in their home countries. Trump declared the crisis a national emergency in February 2019, sparking a debate over whether he could use $2.5 billion in defense funds for border wall construction. The Supreme Court ruled in the administration's favor last month.