By Roberta Rampton

WASHINGTON (Reuters) - Reprising his frequent role of "consoler in chief," President Barack Obama will fly to Orlando on Thursday to meet with survivors of the massacre at a gay nightclub and families of some of the 49 people killed.

The White House said Obama's visit to the Florida city where Omar Mateen pledged allegiance to Islamic State during a three-hour rampage through the Pulse nightclub, was not about the gunman but comforting the victims of the deadliest mass shooting in modern U.S. history.

"This will be, I think, an emotional trip," White House spokesman Josh Earnest told reporters, saying Obama would offer condolences on behalf of the nation.

"The president recognizes that he is a symbol for the rest of the country. But it would be impossible for him not to be personally affected by these kinds of conversations," Earnest said.

A long list of mass shootings has marked Obama's 7-1/2 years in the White House.

Obama most recently met with grieving families in December in San Bernardino, California, after a married couple inspired by Islamic State killed 14 people. He has visited with victims of mass shootings in Texas, Arizona, Colorado, Washington, D.C., and South Carolina.

"Somehow this has become routine," he said last October before meeting privately with victims of a shooting at an Oregon community college where nine people were killed.

"This is a political choice that we make, to allow this to happen every few months in America," he said.

Obama has often said his toughest time as president came after a gunman killed 20 children and six adults at an elementary school in Newtown, Connecticut, in December 2012.

"Every time I think about those kids, it gets me mad," Obama said in January, tears rolling down his cheek, as he launched a push to make gun control an issue in the Nov. 8 election to succeed him.

After Newtown, Obama proposed more background checks for gun sales and pushed to ban more types of military-style assault weapons - a tall order in a country where the constitutional right to own guns is fiercely defended.

He failed to convince enough lawmakers to back the restrictions, and blamed them for being in thrall to the National Rifle Association, the powerful U.S. gun lobby.

The Florida shooting has aroused new debate on gun purchases in the United States, after it emerged that Mateen was legally able to buy an assault rifle even though the FBI had investigated him in the past for possible ties to Islamist militant groups.

Obama said Sunday's massacre was "a further reminder of how easy it is for someone to get their hands on a weapon that lets them shoot people in a school, or in a house of worship, or a movie theater, or in a nightclub."

"We have to make it harder for people who want to kill Americans to get their hands on weapons of war that let them kill dozens of innocents," he said on Tuesday.

(Additional reporting by Timothy Gardner; Editing by Peter Cooney)