A judge previously ruled the Air Force was "60 percent liable" for failing to submit an assault conviction for Devin Patrick Kelley to a national database.
Mike Pompeo says that the American spy agency will not be affected by the closure.
He said that he doesn't know in advance if or when Trump plans to tweet.
The Pentagon is boosting their ranks of special forces and fleets of helicopters and drones.
The president was briefed on the 55-page document, but it's unclear if he has read it.
He referred to the Sutherland Springs shooting in Texas, which took place over a week ago.
At least 500 people were expected to attend the service.
Pence, who believes in prayer for mass shooting victims, has long been a supporter of the right to bear arms.
"What kind of security tops God's protection?" a religion professor asked.
No other mass shooting that is among the 10 deadliest in America's modern history happened in a small town
The president was asked if he could consider tighter legislation on firearms.