Story highlights The incident happened at around 2:20 p.m. local time

Four people were hurt, while the attacker is in critical condition

Police identify attacker as migrant worker with gambling debts

Beijing (CNN) Four passengers were wounded after a man hurled an explosive device at a check-in counter at Shanghai's Pudong International Airport on Sunday afternoon, before attempting to kill himself.

"According to the initial police investigation, a man took out a homemade explosive device in a beer bottle from a bag he was carrying and threw it in front of the check-in counters.

"After the beer bottle exploded, the man took out a dagger from his bag, slashed his own neck and collapsed on the floor," according to a Shanghai Police press statement.

On Monday, police identified the suspect as Zhou Xingbai, a 29-year-old man originally from the southwestern province of Guizhou.

Police said Zhou took several buses to make his way to the Pudong airport on Sunday and committed the crime around 2:26 p.m. near check-in row C at Terminal 2.

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