-- The Pentagon announced there are actually about 11,000 U.S. troops in Afghanistan, much higher than the previously reported 8,400 figure used since last July.
"These changes will help us enhance the trust the public has placed in the department," she added.
Announcing an approximate troop number also allows the Pentagon to deploy whole military units, instead of ones "fragmented in order to meet an arbitrary force management level," McKenzie said.
He said the department weighed "first, openness and transparency with the American people and with our allies, and second, avoiding provision of aid and comfort to the enemy by telegraphing our military capabilities and operations."
But he warned the 11,000 figure is still "an approximation" and does not include future adjustments or unit turnover -- including the additional troops that Mattis will send to Afghanistan as part of the president's new South Asia strategy announced last week.
Mattis has supported sending an additional 3,900 troops to Afghanistan, but since the president's strategy announcement and this new accounting figure of 11,000, the defense secretary has gone back to the Joint Chiefs of Staff asking for revised troop level recommendations.
"If the number changes significantly, we will come back in here to tell you that," McKenzie said, adding "no deployment orders have been issued" yet.
White said Mattis made the decision to reexamine the Pentagon's accounting practices of U.S. troops himself.
"We'll give you an answer when we have them," White said, adding, "The same principles will guide that accounting as well."
Officially, there are approximately 5,000 U.S. troops in Iraq and 500 in Syria, but like in Afghanistan, those numbers are likely higher and will be disclosed later as the new accounting practices are put in place.
"In both theaters, eventually we'll apply the same two pillars: balancing transparency of reporting with a requirement to protect the forces on the ground and give the commander maximum operational flexibility," McKenzie said. "Those numbers will be forthcoming."