The United States Embassy in Manila on Tuesday warned Americans of terrorist groups' plan to conduct kidnappings in Palawan.
"The US Embassy has received credible information that terrorist groups may be planning to conduct kidnapping operations targeting foreign nationals in the areas of Palawan Province, Philippines, to include Puerto Princesa City, and the areas surrounding Puerto Princesa Subterranean River National Park," the advisory said.
It reminded US citizens to "avoid large crowds and gatherings and remain vigilant at all times."
The US Embassy was also the first foreign embassy to issue a travel warning on the threat of kidnappings in Bohol and other parts of Central Visayas.
The advisory was confirmed after a clash between Philippine security forces in the province two days later.
The British Embassy, meanwhile, posted the US Embassy's advisory on its website on Tuesday.
It advised its citizens to "exercise heightened vigilant" in the areas mentioned in the US Embassy's advisory.
The Canadian Embassy also updated its travel advisory on the Philippines, with the US Embassy's advisory.
"If you are travelling to these areas, maintain a high level of vigilance and personal security awareness at all times, report any suspicious behaviour to security forces, follow the instructions of local authorities and ensure that your hotel or resort has adequate security measures in place," it said.
The Philippine National Police said it is validating the US Embassy's information.
The Armed Forces of the Philippines' Western Command, meanwhile, posted a statement on Facebook assuring the public and tourists that Palawan is safe.
The US Embassy did not cite a specific group that may carry out kidnapping operations in Palawan, one of the countries hottest tourist destinations, but the Abu Sayyaf had previously abducted foreigners from the province.
On May 27, 2001, Abu Sayyaf members kidnapped 20 foreign and local tourists from the Dos Palmas Beach Resort in Puerto Princesa City.
Americans Guillermo Sobero and couple Martin and Gracia Burnham were brought by the bandits to Basilan. Sobero was beheaded by the bandits while Martin was killed during a rescue attempt by the military. —Anna Felicia Bajo/ALG, GMA News