The US and Australia have warned of an imminent terrorist attack in the Philippines, where seven hostages were this week beheaded by militants.
The bodies of the dead hostages were recovered on Friday
In an advisory to its citizens the US embassy said an attack could take place anywhere on Mindanao, in the south of the Philippines.
It said intelligence suggested an attack might happen "over the next several days".
Philippine troops have been fighting Islamic militants for months.
One group, Abu Sayyaf, this week sent the heads of seven Christian hostages to the Philippine military on the island of Jolo, off the coast of Mindanao, the military said.
The men, six construction workers and a factory worker, were seized on Monday near the town of Parang in Jolo.
Abu Sayyaf is the smallest of four Muslim rebel groups in the Philippines, with about 400 members.
The group is thought to have links with both al-Qaeda and the regional militant group Jemaah Islamiah, and has been blamed for a number of kidnappings and bombings in the region.
Philippine President Gloria Macapagal Arroyo said that the killings demonstrated the group's ruthlessness.
"Abu Sayyaf's acts of terror will not go unpunished," she said.
In recent months Philippine troops, aided by US counter-terrorism trainers, have carried out extensive work on the island to track down the militants.
In an advisory sent out late on Friday, the US embassy in Manila said a new attack could take place anywhere on Mindanao.
"The embassy has information that a terrorist group may be planning to carry out bombing attacks in central Mindanao over the next several days," the travel notice said.
The Australian Department of Foreign Affairs and Trade said: "Recent credible information indicates terrorists may be in the advanced stages of attack planning. The attacks may be imminent and could occur at any time, anywhere in Mindanao."