WASHINGTON - The parents of American hostage Peter Kassig, who is being held by the Islamic State group, have released a letter he wrote in June in which he said he was "scared to die."
The 26-year-old former US soldier was paraded at the end of an IS video last week that showed the murder of British aid worker Alan Henning.
The video ended with a threat to kill Kassig.
Hostages threatened at the end of four previous, near-identical IS videos have subsequently been murdered.
Kassig's letter referred to his conversion to Islam during captivity, which his parents Ed and Paula Kassig said took place voluntarily at some point between October and December 2013 when he shared a cell with a devout Syrian Muslim.
They noted that Kassig had observed the holy fasting month of Ramadan in July-August 2013 before being taken captive and "spoke of the great impact this spiritual practice had on him."
Kassig also took the Muslim name Abdul-Rahman, and has been following the religion's practices, such as praying five times a day.
"We see this as part (of) our son's long spiritual journey," his parents said in a statement released Saturday.
The Kassigs did not indicate how they obtained the letter, saying they had received it in June and were releasing it now in an effort to "more fully" tell his story to the world.
The militant group has justified killing Western hostages as retaliation for US-led air strikes on the group over swathes of territory it has seized in Iraq and Syria.
"We continue to pressure the government to stop its actions and continue to call on his captors to have mercy and release him," the Kassigs said in releasing portions of their son's June 2 letter.
The text was edited to remove unspecified "sensitive information," though his parents said all words were written by him.
"I am obviously pretty scared to die but the hardest part is not knowing, wondering, hoping and wondering if I should even hope at all. I am very sad all this has happened and for what all of you back home are going through," Kassig writes in the letter.
"If I do die, I figure that at least you and I can seek refuge and comfort in knowing that I went out as a result of trying to alleviate suffering and helping those in need."
Kassig had founded an aid group through which he trained some 150 civilians to provide medical aid to people in Syria. His group also gave food, cooking supplies, clothing and medicine to the needy.
His parents have said he had disappeared in Syria on October 1 last year.
"In terms of my faith, I pray every day and I am not angry about my situation in that sense. I am in a dogmatically complicated situation here, but I am at peace with my belief," Kassig wrote.