TEHRAN (FNA)- World oil prices faced a roller coaster ride this week, tumbling on US demand concerns before rocketing higher on resurgent fears about West’s ultimatum to Iran over the latter’s nuclear energy programs, traders said.

It is unlikely that Iran, being a sovereign state, will yield to the latest deadline of the United States pressurizing Iran to answer an international nuclear incentives offer or face new sanctions.

 President Mahmoud Ahmadinejad said on Saturday that Iran has always welcomed just negotiations.