As Donald Trump heads to the Baton Rouge area hammered by devastating flooding, the state's governor's office cautioned against making the trip for political gain.

"Donald Trump hasn't called the governor to inform him of his visit," Richard Carbo, a spokesman for Democratic Gov. John Bel Edwards's office, said in a statement Thursday night. "We welcome him to La., but not for a photo-op. Instead we hope he'll consider volunteering or making a sizable donation to the La. Flood Relief Fund to help the victims of the storm."

Trump and vice presidential running mate Mike Pence are expected to view some of the damaged areas around midday Friday, though no details have been released.

At least 13 people have died as a result of the flooding in Louisiana, with nearly 40,000 homes damaged. More than 30,000 people have been rescued.

Red Cross is calling the disaster the worst to hit the U.S. since Superstorm Sandy.

President Obama has yet to visit the state, though the White House says he is being constantly updated on the situation while on vacation on Martha's Vineyard. The Advocate newspaper on Wednesday called on Obama to visit "the most anguished state in the union."

FEMA Administrator Craig Fugate visited Louisiana on Wednesday, followed by Homeland Security Secretary Jeh Johnson on Thursday.