Two Florida hospitals will not seek payment of medical bills from the dozens of people treated for injuries suffered in the mass shooting at the Pulse nightclub in Orlando in June, officials at the health facilities said.

The move leaves the hospitals with estimated unreimbursed costs topping $5.5 million, they said on Thursday.

Forty-nine people were killed and 53 were wounded by gunman Omar Mateen before police fatally shot him after a three-hour standoff inside the gay dance club on June 12.

U.S. authorities said Mateen was self-radicalized and acted alone, without assistance or orders from abroad, to commit the deadliest mass shooting in modern U.S. history.

"It was incredible to see how our community came together in the wake of the senseless Pulse shooting," said Daryl Tol, president and CEO of Florida Hospital. "We hope this gesture can add to the heart and goodwill that defines Orlando."

Florida Hospital treated 12 shooting victims at a cost of about $525,400, it said.

Orlando Health said in a statement that it expects to absorb costs exceeding $5 million after payments from funding sources such as insurance plans. Its main hospital, Orlando Regional Medical Center, treated 44 patients at its trauma center located a few blocks from the nightclub.

One patient hurt in the attack remains in guarded condition at the hospital, spokeswoman Sabrina Childress said in an email.

"During this very trying time, many organizations, individuals, and charities have reached out to Orlando Health to show their support," Orlando Health President and CEO David Strong said in a statement. "This is simply our way of paying that kindness forward."

The nightclub remains closed. Former U.S. President Bill Clinton made a quick stop at the memorial outside Pulse on Wednesday, the Orlando Sentinel newspaper reported.