March 27 (Reuters) - U.S. stock index futures were muted on Friday even as investors assessed prospects of de-escalation in the Middle East after another delayed deadline for U.S. strikes on Iran's energy infrastructure.

U.S. President Donald Trump said on 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, failed to calm markets, with oil prices rising once again and government bonds sliding as investors remain skeptical of a deal being struck by the two sides.

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

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

"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 05:33 a.m. ET, Dow E-minis were up 6 points, or 0.01%, S&P 500 E-minis were up 5.5 points, or 0.08% and Nasdaq 100 E-minis were up 11.5 points, or 0.05%.

The oil price spike resulting from the Iran conflict has brought inflation fears to the forefront, complicating the future interest rate cut path of central banks.

Money market participants are not pricing in any easing from the 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 comments from regional Fed Presidents Thomas Barkin, Mary Daly and Anna Paulson.

Among individual movers, Unity Software shares jumped about 15% in premarket trading after the video game software maker reported preliminary revenue for the first quarter above analysts' estimates.

(Reporting by Purvi Agarwal in Bengaluru; Editing by Saumyadeb Chakrabarty)