Iran Oil Sanctions Risk Biggest OPEC Loss Since Libya

European Union sanctions on Iran entered into full force today after exemptions on some contracts and insurance ended, boosting crude prices and pressure on the Persian Gulf nation to halt its nuclear-enrichment program.

The reduction in Iranian exports may become the biggest supply disruption from a member of the Organization of Petroleum Exporting Countries since an armed rebellion all but halted pumping in Libya last year, according to the International Energy Agency. It also comes as a strike by Norwegian workers is curbing flows from North Sea fields.