Manila - Philippine troops have rescued a Roman Catholic priest and another civilian who were among dozens of people abducted in May when hundreds of militants aligned with the Islamic State group laid siege on southern Marawi city, officials said on Sunday.Presidential adviser Jesus Dureza and two senior security officials said without elaborating that troops retrieved the two late on Saturday after a battle to recapture a key mosque and another Islamic building used as a command centre by the gunmen in Marawi.The two security officials spoke on condition of anonymity because they were not authorised to publicly disclose details about the ongoing assaults. The government refused to comment on the reported rescue of the hostages, saying ongoing assaults may be jeopardised and troops and other hostages may be endangered if it releases details.At least 860 people, including more than 660 militants and 147 troops and police, have been killed since the siege began in Marawi, regarded as a centre of Islamic faith in the southern third of the largely Roman Catholic nation. Marawi's central business district and outlying communities now resemble a smouldering wasteland of disfigured buildings and houses.The siege has sparked fears that the Islamic State group may gain a foothold in Southeast Asia by influencing and providing funds to local militants as it suffers battle defeats in Syria and Iraq. The United States and Australia have deployed surveillance aircraft to help Filipino troops battling the Marawi attackers.An army commander, Colonel Romeo Brawner, said on Sunday in a news conference in Marawi that troops were battling to eradicate up to 80 remaining militants who may be holding more than 40 hostages. With fewer fighters, the militants have forced some of their hostages to join the fighting and have resorted to improvised bombs and booby traps to slow the military advance, he said.Father Teresito Soganub was last seen in May in a video, apparently taken under duress by the militants, where he said he was with about 200 other hostages and that his captors wanted the military to withdraw its forces from Marawi."We want to live another day; we want to live another month," Soganub said in the video while standing alone in front of debris and partially burned buildings.