Terminals at Los Angeles International Airport were evacuated briefly late on Sunday before police determined that reports of gunfire in one of the terminals were only "loud noises", the latest false alarm at a busy US airport.

No injuries were reported in the incident but an investigation was underway, Andy Neiman, commanding officer of media relations for the Los Angeles Police Department, said in a Twitter message.

At least two terminals were "self-evacuated" and security personnel were checking them for anything suspicious, according to Officer Alicia Hernandez of the LAX police. She said terminals would reopen to passengers once they were deemed safe.

Video feeds from the airport had shown dozens of people gathered on a tarmac and outside terminals at one of the nation's busiest airports.

The US Federal Aviation Administration said on its website that air traffic to LAX was being delayed at the point of departure. It suggested passengers coming from other cities check with the departure airports.

US airport security officials have been on heightened alert in recent months following deadly attacks at international airports in Belgium and Turkey.

The alert at LAX comes two months after police temporarily evacuated a terminal at New York City's John F Kennedy International Airport while they investigated reports of gunfire in one of its terminals.

A preliminary investigation of that incident, which also occurred on a Sunday evening found no evidence of foul play or suspicious activity.   -Reuters