Over $5.3 million raised for Orlando club shooting victims
Friends and family members embrace outside the Orlando Police Headquarters during the investigation of a shooting at the Pulse nightclub, where people were killed by a gunman, in Orlando, Florida, U.S June 12, 2016. REUTERS/Steve Nesius

Corporate and individual donors have given more than $5.3 million to help victims of Sunday's mass shooting at a gay nightclub in Florida by a gunman who killed 49 people and wounded 53, organizers of fundraising drives said on Tuesday.

U.S. investigators were digging into what motivated Omar Mateen, 29, to attack the Pulse dance club in downtown Orlando, including whether he was inspired by militant Islamist ideology and reports that he may have struggled with his own sexual identity.

Mateen, a U.S. citizen who was born in New York to Afghan parents, was shot dead by police after a three-hour standoff.

The gay rights group Equality Florida set up a page on the fundraising website GoFundMe.com, which had collected $3.6 million from more than 80,000 donors online as of Tuesday afternoon.

"We do not know the total costs for the victims of this horrific hate crime, therefore are working to raise as much as possible and disperse the funds as fast as possible," Equality Florida said in a statement on the fundraising page.

The group said it will work with the National Center for Victims of Crime to distribute the funds.

A representative for Equality Florida could not immediately be reached for further comment.

Separately, a campaign led by Orlando Mayor Buddy Dyer has received donations including $1 million from the Walt Disney Co , which hosts millions of visitors a year at its Walt Disney World Resort in the Orlando area, company and city officials said.

Eligible donations from Disney employees will be also matched by a gifts program of the Walt Disney Company Foundation, the company said.

"We are heartbroken by this tragedy and hope our commitment will help those in the community affected by this senseless act," Bob Chapek, chairman of Walt Disney Parks and Resorts, said in a statement.

Donations to the mayor's OneOrlandoFund will be distributed through the Central Florida Foundation and will support non-profit organizations that are supporting the victims and their families, the Hispanic community as well as the lesbian, gay, bisexual, transgender and queer community, Dyer said in a statement on the Orlando city website.

Aside from Disney's contribution, at least $750,000 in other donations have been made to the OneOrlandoFund fund, Dyer said.

(Reporting by Laila Kearney in New York and Alex Dobuzinskis in Los Angeles; editing by Daniel Wallis and G Crosse)