U.S. stock index futures fell on Thursday as oil prices soared to around $100 a barrel, fanning inflation worries.

Oil prices soared Thursday, briefly trading above $100, and stock markets extended losses as Iran's attempts to hit supplies in the Middle East offset the release of crude reserves by

Oil prices jumped early Thursday despite the record release of emergency reserves by the U.S. and other countries.

U.S. stocks are falling after worries about the war with Iran, with no clear end in sight, briefly sent the price of oil back above $100 per barrel. The S&P

A U.S. military refueling aircraft crashed in western Iraq on Thursday, in an incident U.S. Central Command said involved another aircraft but was not the result of hostile or friendly fire. In a statement,

The price of a barrel of Brent crude oil, the international standard, has topped $100 a barrel again, jolting markets just days after it spiked near $120

The price of oil jumped more than 7%, as the war on Iran was "creating the largest supply disruption in the history of the global oil market."

Attacks on shipping traffic and energy infrastructure in the Persian Gulf temporarily pushed oil back above $100 a barrel, stoking investor fears.