Almost 570,000 people have signed a petition callign for international pressure on Iran to release American pastor Saeed Abedini amid continuing reports that he is being beaten and mistreated in prison, CNSNews.com reports. Iranian authorities are reportedly demanding that he recant his faith in Jesus Christ or spend even longer behind bars than the term he already faces in Iran's brutal Evin prison. Arrested last September while visiting family members in Iran, Abedini -- a convert from Islam to Christianity who moved to the U.S. in 2005 -- was sentenced in January to eight years in prison for "threatening the national security of Iran." The American Center for Law and Justice, which is leading a campaign for his release and representing his wife and children, reports troubling news from relatives' visits for the prison -- reports of continuing beatings, internal bleeding and fainting, denial of medical treatment and death threats from cellmates. A letter from Abedini obtained by the ACLJ earlier this month recounted that prison authorities had told him: "Deny your faith in Jesus Christ and return to Islam or else you will not be released from prison. We will make sure you are kept here even after your eight-year sentence is finished." The ACLJ continues to encourage support for a petition, citing Iran's violation of international treaty obligations and its own constitution, and urging the international community to take "all available diplomatic action to press Iran to respect human rights and release Pastor Saeed."