Philippine police forensic experts were checking if a headless body of a Caucasian man found by villagers in a southern province is that of a Canadian hostage beheaded this week by Muslim extremists, officials said Wednesday.

The body was found beside a dry creek in a mountainous clearing near Talipao town in Sulu province, where Abu Sayyaf militants beheaded John Ridsdel after failing to get a huge ransom by a Monday deadline. Suspected militants later dumped Ridsdel's head in Sulu's Jolo town.

Canadian Prime Minister Justin Trudeau condemned the brutal killing of Ridsdel, who was kidnapped with a fellow Canadian, a Norwegian and a Filipino woman from a southern marina on Samal island in September and taken by boat to Sulu.

In Canada, Trudeau said he spoke with Philippine President Benigno Aquino III about possible actions against the kidnappers.

"The discussions I had with President Aquino and are continuing to have with our allies in the Philippines is the need to bring these criminals to justice and to do whatever we can to express that we are very concerned about security of Canadians," Trudeau said.

The Canadian leader stressed that "we will not pay a ransom."

Troops search for remaining captives

Under increased pressure, thousands of troops have been searching for the militants and their remaining 22 foreign captives, including those abducted with Ridsdel. They face a dilemma of how to wage an offensive against about 400 militants in Sulu's vast jungle without endangering the hostages.

About 2,000 military personnel, backed by UH-1 "Huey" and MG520 rocket-firing helicopters and artillery, are involved in the manhunt for the militants, who are believed to be massing in Sulu's mountainous Patikul town, military officials said.

Amid the crisis, a top army official in Sulu, Brig. Gen. Alan Arrojado, resigned Tuesday from his brigade "due to conflict of approach in addressing the Abu Sayyaf threats" in the province. He did not elaborate.

The Abu Sayyaf began a series of large-scale abductions after it emerged in the early 1990s as an offshoot of a separatist rebellion by minority Muslims in the southern Philippines.

It has been weakened by more than a decade of government offensives, but has endured largely as a result of large ransom and extortion earnings. The United States and the Philippines have both listed the group as a terrorist organization.