The Pentagon says the military is too stretched to both fight insurgents and prepare for war with great world powers.
The creation of a new military force in Syria raises fears of fighting among American allies and could draw the U.S. deeper into the conflict.
President Recep Tayyip Erdogan of Turkey criticized a proposed American-trained force that could put thousands of Kurdish militia on the Turkish border.
When the Islamic State seized territory in Iraq and Syria, it had the time and space to industrialize advanced weapons manufacturing. The results included explosive space heaters and chemical rockets.
The new total counts service members on short-term deployments who were not included in Obama-era troop totals.
President Trump recapped 10 months of his foreign policy in a speech on Wednesday that contained several inaccurate claims.