(Reuters) - U.S. stock index futures extended gains on Friday after a key inflation report showed price pressures rose almost in line with expectations in July, confirming bets on an interest-rate cut at the Federal Reserve's September meeting.

The Personal Consumption Expenditure index, the Fed's preferred measure of inflation, rose 2.5% in July on an annual basis, compared with an estimate of 2.6%, according to economists polled by Reuters. On a monthly basis, it rose 0.2%.

Core PCE, which excludes volatile food and energy components, rose 2.6% last month on an annual basis, compared with expectations of 2.7%.

At 08:33 a.m. ET, Dow E-minis were up 94 points, or 0.23%, Nasdaq 100 E-minis were up 154 points, or 0.79%, and S&P 500 E-minis were up 24 points, or 0.43%.