A bomb made of a plastic bottle and dry ice exploded at Los Angeles International Airport on Tuesday night, making it the second such incident in two nights, NBC Los Angeles reported.

No injuries were immediately reported and no flights were delayed Monday even as the FBI investigated a similar bomb that exploded on Sunday night and delayed flights for several hours.

According to NBC Los Angeles, three dry ice bombs were found in employee bathrooms in the Tom Bradley International Terminal, citing anonymous sources, one of which went off. The bomb was ‘a relatively harmless and simple device,’ the report said, citing LAPD Detective Gus Villanueva.

On Sunday night, a similar bomb exploded in an empty bathroom in a restricted area of the airport not accessible to the general public, according to a NBC report, which cited numerous law enforcement sources as saying that the incident appeared to be a prank but added that the investigation was in its early stages.

LAX is the sixth-busiest airport in the world and the first phase of the new $1.9 billion Tom Bradley International Terminal was inaugurated on Sept. 18, and houses 18 new gates and dozens of luxury retail outlets, according to reports.