The terrorist Abu Sayyaf Group has freed four foreign hostages in southern Philippine province of Sulu after allegedly paying multi-million peso ransom.

Presidential Adviser on the Peace Process Jesus Dureza received Sunday afternoon in Indanan, Sulu Norwegian Kjartan Sekkingstad and the three Indonesian fishermen from Nur Misuari, founding chairman of the Moro National Liberation Front (MNLF).

President Rodrigo Duterte earlier said that Misuari would not be arrested if he resurfaced even if he is a fugitive for allegedly masterminding the Zamboanga siege in 2013.

Dureza said Sekkingstad's release from captivitiy "capped months of quiet, patient but determined efforts with the assistance of all sectors."

However, there were reports that P30 million ransom was paid for the release of the Norwegian, while P20 million for the three Indonesians, identified as Lorens Koten, Teodurus Kofung and Emanuel Arakain.

Presidential Communications Office Secretary Martin Andanar said the government maintains a no-ransom policy in dealing with the kidnappers.

"If a third party (or) the victim's family gave money, we are not aware of it," Andanar said in an interview over dzRB Radyo ng Bayan on Sunday.

The Armed Forces of the Philippines insisted that intense pressure from government security forces forced the Abu Sayyaf to give up Sekkingstad.

The former Norwegian hostage was presented to Duterte in Davao City Sunday night, while the three Indonesians were immediately turned over to their government's representative and went back to Jakarta.

Sekkingstad thanked the Philippine leader for the efforts for his release.

"I express my heartfelt thanks to the President, Secretary Dureza, Chairman Misuari and his finest men," Sekkingstad, who was sporting a long hair, said in a brief statement.

"I am very happy to be alive and free. It's a beautiful feeling," he said.

Sekkingstad, together with Canadian John Ridsdel and Robert Hall, was abducted at a high-end resort on September 21, 2015.

The bandits beheaded Ridsdel and Hall this year after their demand for ransom money was not met. They released Flor last June.

The three Indonesians, on the other hand, were abducted at the vicinity of Lahad Datu in Sabah on July 9.

Military spokesman Brig. Gen. Restituto Padilla said with the release of the four foreigners, the Abu Sayyaf is still holding a total of 16 hostages, including five Indonesians, five Malaysians, a Dutch, and five Filipinos. Emmanuel Tupas, Robina Asido/DMS