When asked whether U.S. gun control measures could have been the key to the Texas shooting, Trump replied, "Mental health is your problem here."
"This isn't a guns situation," he said, before adding, "This is a mental health problem at the highest level. It's a very, very sad event."
At least 26 people were killed and about 20 others were wounded after a gunman opened fire during a Sunday service at a Texas church. The victims ranged in age from 5 to 72-years-old.
Speaking at a joint press conference in Tokyo, Japan, alongside Prime Minister Shinzo Abe, Trump described the shooter as "a very deranged individual."