Iran says it temporarily closed parts of the Strait of Hormuz, the narrow mouth of the Persian Gulf. The move came as semiofficial Iranian news agencies reported live fire exercises in the vital waterway, through which 20% of the world's oil passes.

The move is a rare, perhaps unprecedented shutdown of the strait, a signal from Iran of the potential fallout to the world economy if the United States goes through with threats to attack it as tensions mount between the two countries.