Wall Street was pointing to a red open as investors worried over unrest in Egypt and mulled a partnership between Nokia Corp and Microsoft Corp (MSFT).
Futures for the Dow Jones Industrial Average dropped more than 50 points to 12,137, and the S&P 500 index fell 7.9 points to 1,310.90. The Nasdaq 100 index fell 11.25 points to 2,350.50 in pre-market trading.
World stocks fell for the third straight day on Friday partly on growing tensions in Egypt after President Hosni Mubarak disappointed protesters hoping he would resign, though oil and the dollar advanced. Partly because of the Egypt crisis, Asian stocks were on the course for their biggest weekly loss in nine months, but European shares were more resilient, on track for a second straight week of gains, and safe-haven Swiss francs fell against the dollar after Swiss consumer price inflation eased slightly.
Egypt's people-power protesters, reeling with disillusion and anger, planned massive new demonstrations on Friday that may test the army's loyalties.
"Everyone had hoped the situation in Egypt was going to go smoothly, but the chances of this are small," Koen De Leus, strategist at KBC Securities Bolero in Brussels, said.
"There is going to be nervousness in the market and there are worries of possible contagion in other Middle Eastern countries."
World stocks measured by MSCI All-Country World Index slipped 0.3 percent, down for the third day in a row partly hit by disappointment with corporate earnings. The index, however, is still up 2.8 percent so far this year.
The MSCI emerging market index dropped 0.6 percent, and is down 5.9 percent since the beginning of the year as some investors shift out of the booming emerging markets on concerns over inflation and bet on improving growth in the United States.
MSCI's index of Asia Pacific shares-ex-Japan fell more than 4 percent this week, set for its worst performance since May 2010.
Worries that rising tensions in Egypt could spread disorder to other countries in the oil-rich region sent U.S. crude futures up 1 percent to above $87 a barrel and ICE Brent crude up 0.8 percent to $101.67 per barrel.
"Yesterday, there were the ups and downs of hopes that the situation in Egypt was going to be resolved, but that did not happen," said David Cohen, economist at Action Economics in Singapore.
"So, there's still a degree of uncertainty hanging. The politics in Cairo remains a source of pressure on oil prices."
Higher oil prices would put further pressure on the inflationary situation in emerging economies, threatening to hamper global growth and exaggerate the shift of funds out of emerging markets to developed countries.
The 18th day of unrest in Egypt also helped the dollar, which was up 0.3 percent against a basket of currencies. The U.S. currency was up 0.1 percent at 0.9712 francs.
Yields on 10-year U.S. Treasuries fell 3 basis points to 3.6683 percent.
Egypt five-year credit default swaps rose 39 basis points to 380 bps, CDS monitor Markit said.
In Europe, the FTSEurofirst 300 index eased 0.1 percent, though it is still up 4.2 percent this year, and Portugal's stocks rose 0.2 percent as the country's bond yields stabilised after rising to 7.656 percent on Thursday, topping the previous record set in November.
Ten-year Portuguese debt yield was little changed on the day at 7.344 percent, steady relative to euro zone benchmark German Bunds.
The euro fell 0.4 percent to $1.3538. (Additional reporting by Joanne Frearson, Anirban Nag and William James in London and Seng Li Peng in Singapore; Editing by Toby Chopra)