Police audio has been released revealing that law enforcement in Las Vegas were engaged in a snap operation to secure a route for Joe Biden to get to University Medical hospital, a trauma center, corroborating previous reports that there was some sort of medical emergency involving Biden before he stepped down as the Democratic nominee.

As we highlighted at the time, police sources claimed that US Secret Service informed local law enforcement that there was an emergency situation involving Biden on July 17, and to close necessary streets so that he could be transported immediately to the hospital.

According to the sources, hundreds of officers and employees heard the broadcast live and set in motion emergency response procedures, with radio dispatchers asking for a "surge" of police resources to secure the area and the emergency room on standby.

The plan then abruptly changed and Biden was flown back to Delaware at high speed.

Speculation was that Biden was displaying stroke like symptoms, and that he could have experienced a transient ischaemic attack, also called a "mini stroke", a serious condition where the blood supply to the brain is temporarily disrupted.

The new audio is from the Las Vegas Metro Police Department's protective detail for Biden and was released Friday afternoon by Oversight Project, which obtained the recordings through a Freedom of Information Act request.

The three recordings, containing police chatter, are not time stamped, but appear to span a few hours.