A small explosion at a check-in area of Shanghai’s Pudong airport has injured three people, Chinese authorities said.

The blast at China’s second-busiest airport occurred at about 2:20pm and appeared to have been caused by a homemade explosive, the airport’s management said on its verified microblog account.

It said the three injured people were taken to hospital but gave no details about their condition. There was no disruption to flights in or out of the airport, management said.

Ni Bowen, who had been waiting to check into his Philippine Airlines flight when the explosion happened, said passengers ran for safety after a loud bang rocked the hall.

“At that moment, a beer bottle filled with white smoke rolled right by my feet. I was scared and made off at once,” said Ni, 30, who works for a machinery manufacturer.

Pudong serves international flights but is also a hub for two major domestic airlines.