When Iran appeared close to a preliminary deal with world powers over its nuclear program, France said: Not so fast.

The surprise French move to block the deal exposed divisions among Western negotiators who'd long been in lockstep on the issue.

Analysts say France was motivated by factors including its tough stand against the spread of nuclear weapons, skepticism about Tehran's trustworthiness and the longstanding French tradition of speaking out on the world stage.

After the Geneva talks ended early Sunday with no deal, diplomats including U.S. Secretary of State John Kerry said that progress was nonetheless made and negotiations will continue Nov. 20.

France in recent years has staked out a hard-line stance on Iran's nuclear program after the failure of European-led talks on the issue in the mid-2000s.