NEW YORK -- Iran's foreign minister is ruling out co-operating with the United States in helping Iraq fight Islamic State militants and warning that the terrorist group poses a much broader global threat that needs new thinking to eradicate.

Mohammad Javad Zarif said Wednesday that Iran has serious doubts about the willingness and ability of the United States to react seriously to the "menace" from the Islamic State group "across the board," not just choosing where to confront it as it has just started doing in Iraq.

France wanted Iran to attend a conference Monday in Paris on crushing the Islamic radicals in Iraq but the U.S. said "no."

Zarif called the 24 participating nations at the conference "a coalition of repenters" because most have supported the Islamic State group for years.