drop in global oil prices, driven in part by a boom in U.S. shale oil production, is threatening to hit the economies of energy-exporting Russia and Iran harder than Western economic sanctions have done.. Prices have fallen about 20% on world markets since June because of an increase in oil production and an economic slowdown in Asia and Europe. If that continues, as many analysts expect, gasoline may sell below $3 a gallon at the pump in much of the United States.

The United Nations is unlikely to complete its assessment of whether Iran has conducted research on nuclear weapons before the deadline set by six world powers for a deal to curb the country's nuclear activities, a new complication in the international negotiations.. In its latest quarterly report released Friday, the International Atomic Energy Agency, the U.N.'s nuclear watchdog, said it would conduct a comprehensive "system assessment" of all evidence on the sensitive issue of whether Iran has sought to gain nuclear weapons capability.