President Joe Biden will withdraw U.S. troops from Afghanistan by Sept. 11, the 20th anniversary of the terrorist attacks that precipitated the American invasion that ousted the country’s Taliban leadership, according to people familiar with the plan.

American forces, in conjunction with troops from NATO allies, will begin withdrawing before the end of this month, according to a senior administration official who briefed reporters on Tuesday. The September deadline isn’t “conditions-based” and could be completed early, the official added.

After a review of U.S. policy that Biden ordered after taking office, the administration concluded it could address any terrorist threat emanating from Afghanistan from elsewhere. The official also said the U.S. will work with other countries to protect gains made by women in the country, a major issue given the Taliban largely barred women from education and employment when they were in power.

Read more: Bloomberg