U.S. stock index futures pointed to a lower open Friday as investors remained watchful with concerns that corporate earnings would be affected by the sluggish global economic growth.

The futures on the Dow Jones Industrial Average were down 0.13 percent, the futures on the Standard & Poor's 500 Index were down 0.12 percent and those on the Nasdaq 100 Index were down 0.18 percent.

The National Association of Realtors' home sales report that measures the change in the annualized number of existing residential buildings sold during the previous month will be made public Friday. It is expected to rise to 4.75 million units in September, down from 4.82 million units in August.

On Thursday, the U.S. markets fell with investor sentiment turning negative as the quarterly results reported by Google and Microsoft missed analysts’ expectations. Google reported Thursday that the company’s third quarter profit fell compared to the same period last year as its Motorola business continued to incur operating loss, including severance and restructuring expenses. For the third quarter, the company reported earnings of $3 billion or $9.03 per share, down from $3.18 billion or $9.72 per share for the same period last year and below analysts' expectation of $10.65 per share.

Microsoft also reported Thursday that the company’s first quarter profit declined 22 percent compared to the same period last year as its personal computer business was affected by the soft market demand. For the first quarter, the company reported revenues of $16.1 billion and earnings per share of $0.53 below analysts’ expectation of $16.42 billion revenue and 0.56 cents earnings per share.

Meanwhile, according to data reported Thursday by the Labor Department, the initial jobless claims rose to 388,000 in the week ending Oct. 13, up from 342,000 in the previous week. The Dow Jones Industrial Average marginally fell 0.06 percent, the S&P 500 Index was down 0.24 percent and the Nasdaq Composite Index declined 1.01 percent.

European markets fell Friday as investors maintained a cautious mode awaiting results of the European Council Summit that concludes in Brussels. The summit is expected to announce measures to control the debt crisis affecting the euro zone. London's FTSE 100 was down 2.92 points, Germany's DAX 30 index fell 17.26 points and France's CAC 40 dropped 1.85 points.

Asian stocks were mixed Friday following global cues. Hong Kong's Hang Seng was up 31.03 points, Japan's Nikkei Stock Average rose 19.82 points and South Korea’s KOSPI Composite Index declined 15.28 points.