President Barack Obama said he was also eager for a firsthand look at the damage done by floods that damaged more than 40,000 homes and killed at least 13 people, announcing plans to visit Baton Rouge on Tuesday.
Obama's travel requires a massive retinue of Secret Service agents and assistance from local and state law enforcement officials, so the White House usually waits to visit disaster zones to avoid tying up police and emergency resources needed elsewhere.
On Friday, Trump's motorcade drove past piles of possessions and building materials that had been ripped out of flooded homes en route to Greenwell Springs Baptist Church in a hard-hit portion of East Baton Rouge Parish.
"You're going to be fine," Trump told several dozen supporters gathered outside, many asking for autographs and selfies.
The deluge that dumped more than 2-1/2 feet (0.76 meter) on parts of Louisiana has been described as the worst U.S. disaster since Superstorm Sandy in 2012.
Trump told reporters he came to help out, joined by vice presidential running mate, Indiana Governor Mike Pence, in a visit to a state that is typically a Republican stronghold in presidential elections.
Louisiana Governor John Bel Edwards' office, however says Trump did not call to discuss plans.