Five people were injured in an explosion at Shanghai Pudong International Airport Sunday afternoon, authorities said.

An armed policeman stands guard at the site where an explosion happened at Shanghai Pudong International Airport in east China's Shanghai, June 12, 2016. Three passengers were injured after an explosion at Shanghai Pudong International Airport on Sunday afternoon, authorities said. [Xinhua]

The explosion happened at around 2:26 p.m. when a man threw a homemade beer bottle explosive to a check-in counter in Terminal 2, the Shanghai Municipal Public Security Bureau said in a statement Sunday evening.

After the explosion, the man took a knife from his backpack, cut his neck and then fell to the ground, police said.

The suspect, now in critical condition, was under emergency treatment.

Four passengers, including a Philippine national, were slightly injured by shards of glass and were being treated in hospital.

A further investigation is under way.

A few flights were affected as their passengers were scheduled to check in at the explosion site, but the airport is now in normal operation.