About 2,500 Afghans who worked for the U.S. government will be evacuated to a military base in Virginia along with their families pending approval of their visas, the Biden administration said Monday as the administration rapidly moves to complete the withdrawal of U.S. forces from Afghanistan.

Members of Congress have expressed alarm about the fate of Afghans who worked for the U.S. over the past 20 years, particularly as the Taliban have stepped up military operations against the Afghan government, seizing control of major portions of the country as U.S. troops withdraw.

The Afghans will be temporarily housed at Fort Lee, a sprawling Army base south of Richmond starting next week, according to a Defense Department notice sent to Congress. The administration announced earlier this month that it would soon begin relocating Afghan visa seekers under an initiative known as “Operation Allies Refuge.”

The group includes 700 Afghans who worked for the U.S. and roughly 1,800 family members.

“These are brave Afghans and their families, as we have said, whose service to the United States has been certified by the embassy in Kabul, and who have completed thorough security vetting processes,” State Department spokesman Ned Price told reporters.

Pentagon press secretary John Kirby declined to say when the first applicants would arrive at Fort Lee but said they are expected to stay only several days before being resettled by the State Department and refugee assistance groups. Kirby said it is possible the Pentagon will offer additional domestic military bases for similar use depending on the pace of relocations.

Monday's announcement came amid growing concerns for the safety of Afghans who served as translators and in other support roles for American troops and diplomats during the long war.

The group to be housed at Fort Lee make up just a small portion of the number of Afghans seeking refuge in the United States. Roughly 20,000 have expressed interest in applying for “Special Immigrant Visas” to move to the U.S., but only about half are far enough along in the vetting process to be considered for relocation.

An additional 4,000 applicants and family who have completed most of the application process but have yet to clear security screening will be sent to non-U.S. locations to await adjudication of their visas, Price said. “Our plan is to take them to locations outside of the United States where they will be safe and where they will be provided accommodation during this processing period, which can last a number of months," he said.