A young priest who Pope Francis called by phone and encouraged to fight cancer has died. He was 35.

Chilean priest Francisco Rencoret passed away on Aug. 13 after battling cancer. Rencoret, who was ordained in 2013, was studying Canon Law at the Gregorian University in Rome when he was diagnosed with the disease.

He returned to Chile for treatment.

Rencoret's chances of recovery were high in recent weeks based on test results showing that there was improvement in the sarcoma with metastasis in his lungs, the Catholic News Agency reported.

However, his brain tumours eventually caused his death.

Pope Francis called Rencoret in June. The priest said the Pope learned about his disease and called him to "find out about my health and to tell me that he was praying for me, to give me a lot of support, encouragement and the love of the Church."

Rencoret told Pope Francis that "I am offering some of my sufferings for your vocation, difficulties and sorrows" and that they were "very much in communion because in fact God is merciful."

Father Mauricio Valdivia, his friend and fellow student at the Santiago Pontifical Major Seminary, said the priest's aim was not to be cured but be saved.

"I believe that (he) was able to understand in one way or another, not without difficulty, that God gave him the gift of this time to prepare himself, and I believe the time was ripe for him to meet the Lord," Valdivia said.

He added, "He experienced such a radical self-surrender since he said that he wanted to be saved more than he wanted to be cured, and from that perspective he experienced it as a privileged opportunity. He always looked very peaceful."

Before his death, Rencoret prepared his family by conveying to them peace and strength, Valdivia said.

"(I even) had the opportunity to go with him to the clinic, I stayed once overnight there with him and we talked about a lot of things and heard each other's confessions, in that gift of priestly friendship, with that tranquility of the heart of knowing how to seek God's will," he added.

Valdivia described Rencoret as someone who was very compassionate towards the needy.

"There was no beggar in the parish who didn't know Pancho. He helped a network of street people," he said.

He recalled that Rencoret brought clothes and things to a man who was bedridden, a selfless act that he did for others as well.

"His friendship was a blessing to me," Valdivia said.

Rencoret's wake was held at the Saint Vincent Parish in Santiago.