U.S. Defense Secretary Lloyd Austin told Congress on Thursday that America’s troop withdrawal from Afghanistan is “slightly” ahead of schedule, but he provided no details.

While President Joe Biden has ordered a full U.S. troop withdrawal by September 11, Austin did not say when the retrograde may be complete.

Austin said at a House Appropriations subcommittee hearing that the Defense Department’s proposed $715 billion budget will include money to help the military develop the capabilities to prevent attacks against the United States by terrorist groups in Afghanistan, AP reported.

With the defense department’s budget set to be released Friday, Austin provided few spending specifics to committee members asking about various priorities.

U.S. military commanders have said they will monitor and counter threats from al-Qaeda and the Islamic State (Daesh) group from outside the country once U.S. forces leave Afghanistan.

So far, officials have acknowledged that the U.S. does not yet have any agreements for basing or overflights from any of Afghanistan’s neighboring countries, AP reported.

On Wedensday, the U.S. Central Command (CENTCOM) said week that it has “completed between 16-25 percent of the entire retrograde process.”

CENTCOM said in a statement the United States Department of Defense has retrograded the equivalent of approximately 160 C-17 loads of material out of Afghanistan and has turned over more than 10,000 pieces of equipment to the Defense Logistics Agency for disposition.

The U.S. has officially handed over five facilities to the Afghan Ministry of Defense, the statement said.

CENTCOM did not elaborate on the installations.

“For operational security reasons we will only be providing an approximate range of the percentage of the exit process that is complete,” the statement noted.

“As the responsible and orderly exit continues, the size of the range will increase to preserve operational security. This update includes the progress on the retrograde of troops and equipment from Afghanistan, the turning over of equipment and facilities to the ANDSF, as well as the destruction of some equipment,” the statement concluded.