President Trump said the army secretary, Mark Esper, will come in as acting secretary of defense.
Acting US Defense chief Patrick Shanahan is one of several Pentagon chiefs to take aim at China during the Singapore conference.
The COMCASA agreement is expected to help India to obtain critical defence technologies from the US and access critical communication network.
While flying to Texas, Patrick Shanahan dismissed any suggestion that active-duty forces will extend their mission for the long haul.
Moreover, actual sexual assaults were likely to be about triple the reported number, given the estimate that just one out of three victims in the military file a complaint.
The Department of Homeland Security asked the Pentagon to build 57 miles (92 kilometers) of 18-foot (5.5-meter) fencing, build and improve roads, and install lighting to support Trump.
The announcement comes days after James Mattis stepped down as the US Secretary of Defense on December 21.