President Biden said Sunday that the U.S. military is “executing a plan” to move stranded American citizens to the Kabul airport in greater numbers, including through an expansion of a safe zone around the facility and by creating conduits for people to access the compound “safely and effectively.”

“Our first priority in Kabul,” Biden said in remarks at the White House, “is getting American citizens out of the country as quickly and as safely as possible.”

The president would not say how the plan for “increased rational access to the airport” is being carried out or whether U.S. troops have expanded their perimeter outside the airport and further into Kabul, which could put them at heightened risk of attack from Taliban factions manning security checkpoints and Islamic State operatives who, U.S. officials warn, pose a serious threat.