Former U.S. President Jimmy Carter is backing a historic deal aimed at curbing Iran's nuclear program, calling it "a major step in the right direction."

Carter told The Associated Press on Wednesday that he's confident the agreement allows any violations by Iran to be detected. Carter says the White House briefed him on the deal Tuesday.

The 90-year-old Carter calls the deal better for Iran, the U.S., and the world, and says he's thankful for it.

The Iranian hostage crisis dominated Carter's 1980 campaign for a second term. He was defeated by Republican Ronald Reagan.

In a new book released this month, Carter writes that the crisis made him vulnerable to attacks labeling him ineffective. He calls his final year in office "the most stressful and unpleasant" of his life.