A loud noise triggered a stampede Monday at the international airport in Mexico’s popular tourist destination of Cancún. The country’s National Guard said there was no evidence that gunshots were fired, and the noise could have been a tourist tipping over some signs, according to Reuters.

The national guard was investigating the incident, according to Reuters.

CBS News producer Guy Campanile, who was at the airport during the commotion, told CBS News Radio the disturbance sent hundreds scrambling.

Elderly tourists were knocked down and small children were separated from adults, Campanile reports. Several people appeared to suffer injuries from being trampled, he said.

Crowds sought safety on the tarmac, and buses carried travelers to other parts of the airport, he said.

Throughout the terminal where the disturbance occurred, Campanile said he saw passports, boarding passes and shoes scattered on the floor.

Airport employees were gathering the documents and placing them on counters, he said.