The U.S. dollar gained against the euro on Friday on lingering concerns about the euro zone debt crisis while crude oil futures slipped below $125 a barrel as fears eased of a supply disruption from Saudi Arabia, the world's biggest oil exporter.

The dollar also climbed to a nine-month high against the yen after Japanese data for January showed the fourth consecutive month of core consumer price declines, suggesting the Bank of Japan will focus on monetary easing, a policy which will weaken the yen.

The dollar strengthened this week against both the euro and the yen after U.S. Federal Reserve Chairman Ben Bernanke stopped short of signalling more monetary stimulus to prop up the U.S. economy.

The euro was down 0.90 percent at $1.3191, while against the yen, the dollar was up 0.70 percent at 81.64.

Crude futures fell after surging 5 percent to an 11-month high on Thursday after an Iranian media report of a pipeline fire in Saudi Arabia. Prices later retreated after CNBC cited a Saudi oil official saying the report was untrue.

Brent crude futures sank almost 2 percent to $124.28 a barrel on Friday. U.S. light sweet crude oil fell $1.50 to $107.34 a barrel.

U.S. stocks opened slightly lower even as Wall Street was on track to close its ninth straight week of gains, the longest such run since January 2004.

The Dow Jones industrial average <.DJI> was down 6.10 points, or 0.05 percent, at 12,974.20. The Standard & Poor's 500 Index <.SPX> was down 0.47 points, or 0.03 percent, at 1,373.62. The Nasdaq Composite Index <.IXIC> was up 3.45 points, or 0.12 percent, at 2,992.42.

U.S. Treasury debt prices rose after a three-day losing streak, with long-dated government debt supported by scheduled purchases of 30-year bonds by the Fed as it attempts to stimulate lending and economic growth.

The benchmark 10-year U.S. Treasury note was up 13/32 in price to yield 1.9843 percent.

Gold edged lower, unable to sustain Thursday's rebound after the massive selloff a day earlier. Spot gold, which tracks trades in bullion, was down 0.2 percent. For the week, it was headed for a 4 percent loss, mainly due to Wednesday's 5 percent plunge, its biggest one-day loss in more than 3 years.