Syrian forces believe suspects are linked to a suicide bombing in January in the city of Manbij.
It wasn't immediately clear whether the Defense Department inspector general would open an investigation into the acting defense secretary's handling of matters related to his former employer.
The change to an executive order removes the requirement for public accounting on CIA drone strikes.
Defense officials are examining a proposal to shift $3.6 billion in military construction funds to fortify the border.
The decision is a partial reversal of the president’s plan to end the U.S. military mission there.
White House announcement comes after European allies said they would withdraw forces unless the U.S. remained.
As pullout deadline looms, some U.S. officials and lawmakers say Trump should rethink his plans.
The initiative would be at odds with the assessment of U.S. intelligence and defense communities.
Critics point to Patrick Shanahan’s limited foreign policy experience, but his boss might see that as a plus.
The phrase 'climate change' appeared in a draft Pentagon report 23 times. The final version used it once.