No final decision has been made to deploy additional troops to Eastern Europe as the world prepares for a potential Russian attack on Ukraine, but Defense Secretary Lloyd Austin has put 8,500 service members on alert they may be deployed, the Pentagon said Monday.

“We wanted to make sure that we were ready in case that call should come, and that means making sure that units that would contribute to it are as ready as they can be on as short a notice as possible,” Pentagon Press Secretary John Kirby said, according to Military.com.

Kirby told reporters “a range of units” across the U.S. have been put on heightened alert, including Army brigade combat teams and other units to manage logistics, medical, aviation and transportation.

Army photo by Maj. Jason Elmore