Police and park authorities temporarily closed off the tourist attraction after the bomb disposal unit decided to explode the device.
Senior Superintendent Atanacio Macalan Jr., Palawan’s provincial police director, said they were still conducting an investigation on the incident.
Western Command Commander Lt. Gen. Rustico Guerrero said the bomb was isolated after a civilian called attention to a suspicious package and a Philippine Coast Guard sniffing dog alerted authorities.
“It was (handled) safely and nobody was hurt,” Guerrero said.
“It was an improvised grenade. Our personnel on the ground decided to detonate it,” he added.