During a time of crisis in a foreign country, U.S. citizens are instructed to notify the local U.S. Embassy of their presence so diplomats can work to assist them. That creates a database for the United States to estimate the number of Americans in need of help. In media briefings, the State Department has declined to divulge its estimates of Americans in Afghanistan.

According to the aides, the administration officials — from the State and Defense departments, as well as the National Security Council and the Joint Chiefs of Staff — also told the assembled Senate staffers that there is no plan to evacuate Americans who are outside Kabul, as they do not have a way of getting through the Taliban checkpoints outside the Afghan capital.

Officials did not specify how many Americans are outside Kabul, the aides said. The briefing, which was held Tuesday morning and attended by aides representing a wide swath of Senate offices, lasted half an hour.