Eight people were injured in an explosion at the front porch of a nightspot in IOI Boulevard here.
Selangor deputy CPO Deputy Comm Datuk Abd Rahim Jaafar said the incident occurred at about 2.15am, Tuesday.
It is learnt that patrons of the establishment were watching a Euro 2016 football match when the explosion occurred.
Puchong Fire and Rescue Department chief of operations Mohd Hisam Mat Yasih said a distress call was received at about 3am.
DCP Rahim confirmed the explosion was caused by a hand grenade.
A security guard working at the area said he saw smoke billowing from the nightspot after the explosion.
He said he saw three patrons injured by shards of broken glass.
A staff member of the nightspot said there were more than 20 patrons at the establishment, which was screening the Round of 16 match between Spain and Italy.