
Quoting eyewitnesses, police said two men on a motorcycle approached the shop and the rider threw a grenade at tables on a sidewalk connected to the beachfront food shop.
The grenade used was a US-made M-61, judging from the safety lever left at the scene.
Police, medics and rescue workers had to wait briefly before securing the scene and treating the wounded until an abandoned motorcycle could be inspected for explosives, but none were found. Remote detonation of a secondary explosion is a common tactic.
The three girls were not seriously hurt and could be treated at a local hospital.
The area had been targeted by an attack on October 15, but the grenade used was a dud, police said.