Patrons trapped in the bathroom of an Orlando nightclub as a gunman carried out the worst mass shooting in modern U.S. history begged 911 operators to send help.

The last batch of 911 audio recordings released Wednesday by the city of Orlando captures patrons desperately waiting for first responders.

The operators repeatedly tell them help is on the way but that there are a lot of people to rescue in the club, as well as many hiding places.

Even though an off-duty officer was working at the Pulse nightclub and other officers responded within minutes, the standoff with gunman Omar Mateen lasted three hours.

During that time, patrons told 911 operators that the conditions of the wounded were getting worse.

Forty-nine people were killed and 53 others were seriously injured.