Abdul Rahim Jaafar, state deputy police chief, told AFP that the attack on the Movida restaurant in busy Puchong district was probably the result of a business conflict or revenge.
"Eight people were injured in the hand grenade attack early Tuesday. One of them, a man, is in serious condition," he said.
Abdul Rahim said initial investigations revealed that the assailant threw the explosive at a particular couple in the outlet.
"I rule out terror attack. The blast is likely motivated by business rivalry among the local gangsters or a revenge attack," he said.
News reports said the blast occurred when some 20 patrons in the restaurant were watching Italy play Spain in the Euro 2016.
In a similar attack in 2014, a Malaysian man was killed and 13 people, including Singaporean, Thai and Chinese tourists were injured, after a bomb exploded in front of a pub in Kuala Lumpur.
- AFP