The Pentagon is expected to release a memo on Monday announcing it will require U.S. military members to get vaccinated against coronavirus “no later than” Sept. 15.

The call for inoculations could be accelerated if the vaccine receives final FDA approval sooner, Defense Secretary Lloyd Austin said.

Pfizer is expected to obtain final FDA approval for its COVID-19 vaccine early next month. Without the agency’s approval, Austin would need a waiver from Biden to mandate shots.

Austin’s memo comes just over a week after President Biden urged defense officials to develop a plan requiring troops to get jabbed to shore up vaccinations in the federal workforce. Biden also ordered for additional restrictions to be placed on unvaccinated federal personnel that will include wearing masks, social distancing and travel limits, Austin said in the memo.