The rial's drop in value coincides with a plunge in oil prices; crude oil exports provide some 50 percent of Iran's budget.

He is working from a list that includes former Deputy Defense Secretary Ashton Carter, who is widely seen as the front-runner.

PII is often collected, by foreign states, for the purpose of attempting to use U.S. citizens as spies whether they are aware of it or not.

The head of Gazprom, Alexei Miller, later confirmed that the pipeline was finished. "The project is closed," he told reporters.