Catholic bishops in the Philippines lashed out on Tuesday at a presidential candidate popularly known as "Dirty Harry," after he made a rambling and obscenity-filled speech cursing the pope. Rodrigo Duterte, whose hard-line anti-crime reputation has seen him compared with Clint Eastwood's no-nonsense enforcer, sparked the ire of the influential Catholic Bishops Conference of the Philippines, which questioned if he deserved to be president. "When a revered and loved and admired man like Pope Francis is cursed by a political candidate and the audience laughs, I can only bow my head and grieve in great shame," said a statement, issued by the group's president, Archbishop Socrates Villegas. The comments are a rare personal criticism of a presidential candidate from senior church leaders in the largely-Roman Catholic nation. Duterte, the longtime mayor of the southern city of Davao, declared his intention on Monday to run for president in the 2016 election, referencing a January visit to Manila by Pope Francis, whom he blamed for a massive traffic jam. "Pope, you son of a whore, why don't you go home," he said, to the guffaws of a crowd of supporters. Duterte also boasted of having mistresses and of killing suspected criminals, a frequent accusation leveled against him by human rights advocates. The bishops said these remarks raised further questions about Duterte. "Killing people is corruption. Killing is a crime and a sin whether it is done by criminals or public officials no matter what the intention. Adultery is corruption... Vulgarity is corruption," the statement said. "Is this the leadership by example that Mayor Duterte excites in us? Is this the leadership by example that makes a public official deserving of the title "Honourable"? it added. Duterte has served as mayor for the sprawling southern city of Davao on and off since he was first elected in 1998. He is one of several candidates vying to succeed Benigno Aquino, whose single six-year term ends next year. Surveys show Duterte is a serious contender. Duterte has openly boasted of his ferocity towards criminals, even as rights advocates say that he tolerates or controls "death squads" who kill suspected criminals in his city. In a report earlier this year, Human Rights Watch said Duterte's so-called "Davao Death Squad" had killed more than 1,000 people during his tenure as mayor of the city. The Philippines has long been saddled with a "culture of impunity" where powerful figures feel they can kill people without fear of punishment.