The American security services have uncovered a threat against Pope Francis ahead of his visit to the United States this month. Michael McCaul, chairman of the House Committee on Homeland Security, made the announcement yesterday, warning that authorities were concerned about the Pope's security due to his habit of mingling with the people on walkabouts. "He's a very compassionate man. He likes to get out with the people," McCaul told ABC's This Week talk show. "With that comes a large security risk. We're monitoring very closely threats against the Pope as he comes into the United States. We have disrupted one particular case." McCaul said he learned of the threat from the US Secret Service, adding that security authorities "will be very diligent to protect (the Pope) as he comes into the United States." No more details were given about the nature of the threat to Francis, although ISIS have previously made death threats against him. The Holy Father arrives in the US on September 22.