U.S. stock index futures edged lower Friday as investors assessed prospects of de-escalation in the Middle East after another postponed deadline for U.S. strikes on Iran's energyinfrastructure.

President Donald Trump said Thursday he would again extend a deadline for Iran to reopen the Strait of Hormuz or face the destruction of its energy plants, after Tehran earlier rejected a 15-point U.S. proposal to end the fighting.

The delay, however, did little to calm markets, with oil prices rising again as investors remained skeptical of the two sides striking a deal.

The S&P 500 and the Nasdaq stayed on track for their fifth week of losses as the month-long Iran war dragged on. The Dow was set for weekly gains.

On Thursday, the S&P 500 and the Dow closed more than 1% lower each, while the Nasdaq ended over 10% lower from its record close, confirming it had been in correction territory.

The Russell 2000, the first on the correction path, confirmed it last Friday.

"Words alone aren't cutting it right now, with President Trump's extension of the pause on Iran energy strikes failing to lift the mood in any meaningful way. Tangible evidence of progress is what's needed," said Matt Britzman, senior equity analyst, Hargreaves Lansdown.

At 8:33 a.m. EST, Dow E-minis fell 195 points, or 0.42%, S&P 500 E-minis lost 28.75 points, or 0.44%, and Nasdaq 100 E-minis were down 153.25 points, or 0.64%.

The spike in oil prices resulting from the Iran conflict has brought inflation fears to the forefront, complicating the future rate-cut path for central banks.

Money market participants are not pricing in any easing from the U.S. Federal Reserve this year, compared with two cuts anticipated before the war broke out, according to CME's FedWatch Group.

Investors will look out for the final reading of the University of Michigan's sentiment survey for March and examine commentary from regional Fed Presidents Thomas Barkin, Mary Daly and Anna Paulson.

In individual movers, Unity Software's shares jumped about 12.3% in premarket trading after the maker of videogame software reported first-quarter preliminary revenue above analysts' estimates.