The Department of Defense announced new policies on Friday for foreigners who plan to enter the United States military.

The department's chief of accessions Stephanie Miller made the announcement, which concerns the Military Accessions Vital to National Interest (MAVNI) and green card holders. The new change puts increased security screenings on applicants who desire to eventually obtain American citizenship.

Miller said that the Department of Defense had to change the policy because some service members were receiving citizenship before they passed their security clearance. Some in the service currently who have received their characterization of service have now had theirs decertified while waiting on new ones.

The MAVNI program allows certain foreigners with special skills needed by the U.S. military to enter, and it was implemented in 2016.

The changes will, according to Miller, place "the highest emphasis on security and suitability screening with all current and prospective service members, as well as the value of military service, in receiving U.S. citizenship."

"Effective immediately, all green card holders must complete a background investigation and receive a favorable military suitability determination prior to entering any component of the armed forces," Miller said.

Prior to the new change, applicants could begin their basic military training while the background check had been initiated. Now, green card holders will need to enter the delayed entry program for even longer, while they wait for security clearances from the Office of Personnel Management. The backlog for clearances now is up to a year.

Both green card holders and MAVNI members will still be able to have a path to citizenship for their military service; however, instead of being able to apply after just a few days of service, these individuals must now wait at least 180 days for a characterization of service to be issued. An "honorable" categorization places the member on the path to citizenship.

"We will not grant a characterization of service until 180 days," Miller said. "It doesn't make a whole lot of sense for us to wait to give a characterization of service for everybody else at 180 days, but for non-U.S. citizens, we would be granting a characterization well short of 180 days."

U.S. citizens also have to wait for 180 days of service for a characterization of service.

Military Times reporter Tara Copp tweeted on Friday that Secretary of Defense James Mattis is intending on keeping the MAVNI program.