Wall Street set for rocky ride; all eyes on jobs report

U.S. stock index futures pointed to a sharply lower open on Friday ahead of nonfarm payrolls -- one of the most significant data releases of the summer which will be closely watched for its implications on the timing of the first rate hike since 2006.

Dow futures slumped around 170 points as traders geared up for August's jobs data, due at 8:30 a.m. ET. It will be the final read on monthly labor conditions before the Federal Reserve makes a decision on interest rates at its next policy meeting in about two weeks.

Analysts polled by Thomson Reuters expect a slight increase in nonfarm payrolls to 220,000 in August, with unemployment ticking down to 5.2 percent and average hourly earnings increasing at a steady 0.2 percent.