The group recently released Jordanian journalist Baker Atyani, who was held captive for a year and a half. He was abducted in June 2012 by the Abu Sayyaf group, reports Xinhua.
The Philippine military are trying to rescue the rest 17 hostages, said Jose Johriel Cenabre, commander of the Second Marine Brigade.
But Cenabre failed to say when they can rescue the hostages, including Dutchman Elwold Horn and Swiss national Lorenzo Vinciguerra, who were abducted in Feb 2012.
"Our operations are intelligence-driven. We are not operating as if we do not value human lives," said Cenabre.
The 380-strong Abu Sayyaf founded in the early 1990s is a Muslim terrorist group operating in the southern Philippines, engaging in kidnappings for ransom, bombings, assassinations, and extortion.