DJIA: Futures Fall on Greek Bailout Talks' Setback, Iran Sanctions Already Hitting Oil Trade Flows

Stock index futures fell on Friday as the latest setback in Greek negotiations for a financial bailout package put the S&P 500 on track to snap a three-day winning streak.

Greece's financial future has been thrown back into turmoil after politicians were forced to look again at the austerity deal on offer after eurozone finance ministers said the cuts did not go far enough.

British bank Barclays is set to miss a key profit target after its investment bank ended 2011 with its worst quarter for three years.

Sanctions on Iran are already hitting global oil flows even though a European ban on imports from the Islamic Republic does not come into effect until July, the International Energy Agency (IEA) says.