MANILA - A Catholic priest rescued by Philippine troops from the war-torn southern city of Marawi was flown to Manila on Monday (Sept 18), nearly four months after he was abducted by militants from the Islamic State in Iraq and Syria (ISIS).

Appearing upbeat and in good health despite his ordeal, Reverend Teresito "Chito" Soganub, 51, told reporters who asked how he was: "I am physically strong and handsome. That's it for now."

"Thank you, and I pray for you. God bless you all. Pray for me, for my recovery," he added, before he was whisked away for a "custodial debriefing".

Father Soganub, vicar-general of Marawi, was rescued at around 11.45pm on Saturday, hours after Philippine troops retook a mosque which the ISIS militants were using as an "assembly point and storage of combat supply", Defence Secretary Delfin Lorenzana said at a news conference.

He was found with another hostage Lordbin Noblesa Acopio, a 29-year-old teacher.

Military chief General Eduardo Ano disclosed that Father Soganub's rescue was "a deliberate effort". Special forces units had planned to "extricate" the priest as early as last Wednesday before they were to assault the mosque, he said.

But Father Soganub's guards moved him and so the plan was shelved. The army decided to press on with the assault on the mosque, hoping they could rescue the priest during the fighting.

Gen Ano said there were at least 12 more hostages being held inside a network of tunnels and chambers beneath the mosque.

"We are concentrating our efforts on rescuing them, as well as other hostages in other buildings. We'll try to rescue them alive," he said.

Father Soganub was taken hostage along with about a dozen of his parishioners after hundreds of armed extremists flying the black flag of ISIS overran Marawi, the Islamic capital of the mainly Catholic Philippines, on May 23.

In June, the priest appeared in a video asking President Rodrigo to stop the military air raids.

"Mr President, we are in the midst of this war," he said in the video, adding that the bombing put the hostages at risk. "We want to live another year, two years."

Photos showing him, a young man and a woman slumped against a wall had also circulated on the internet.

Accounts cited by the military of hostages who either escaped or were rescued said the militants had forced them to convert to Islam and carry wounded fighters to mosques. Women who were held hostage were forced to marry militants.

One hostage said Father Soganub was forced by his captors to do the job of a cook, according to an army spokesman.