MANILA - The United States warned its citizens Thursday of a "series of credible security threats" in the restive southern region of the Philippines, where a Muslim insurgency has raged for decades.
The warning came on the eve of a planned visit to Manila by US Secretary of State John Kerry, although embassy officials declined to comment on whether the warning would affect the trip.
Kerry is not scheduled to visit the areas mentioned in the warning, according to his official schedule released by the Philippine foreign department.
"Individuals associated with known extremist and insurgent groups are believed to have been conducting surveillance on a number of public locations in these areas, as possible targets of interest," the US embassy in Manila said in an emergency message.
These include "high-profile sporting events, residential areas, business offices, hotels, clubs, restaurants, places of worship, schools, public areas, and other destinations, whether frequented by foreigners or locals".
It added: "Extremists may elect to use conventional or non-conventional weapons, and target both official and private interests."
As a result, the embassy said it was restricting travel by US government staff to certain parts of the southern region of Mindanao.
The embassy warning named Davao, Mindanao's largest city, and four Mindanao provinces, including areas not known as hotbeds of insurgency.
Tens of thousands of Americans live in the Philippines, a former US colony, including some who stay in parts of Mindanao that are not usually affected by insurgencies.