Oil prices fell as US refineries began restarting production following disruptions, but losses were capped by falling US crude reserves and geopolitical jitters in Nigeria.

Gold: The price of gold advanced. "The precious metals complex put in a positive performance," said Barclays Capital analyst Suki Cooper, adding that "gold prices rose as prices tracked dollar weakness."

On the London Bullion Market, gold climbed to 666.50 dollars an ounce at Friday's late fixing, from 655.30 dollars a week earlier.

Oil: Crude oil prices slid on an easing supply picture.

Brent North Sea crude for July delivery fell to 67.91 dollars per barrel on Friday, compared with 70.69 dollars per barrel at the close on Friday of the previous week.

New York's main oil futures contract, light sweet crude for delivery in July, sank to 64.33 dollars per barrel, from 65.20 dollars a barrel the previous week.

Several major oil companies, such as ConocoPhillips, Citgo and Valero, announced that problems at their refineries in the United States had been resolved.

And British energy giant BP's vast Prudhoe Bay oil field in Alaska was back to operating at full capacity after a recent water pipe leak.

London Brent crude had neared 72 dollars per barrel last week as traders fretted over below-normal levels of gasoline reserves heading into the peak-demand driving season in the United States.

Sucden analyst Michael Davies added: "The market continues to draw support from geopolitical concern and especially from civil unrest in Nigeria."

Nigeria is the world's sixth biggest crude producer and the biggest on the African continent, but unrest has cut the country's production by about 25 percent.

Sugar: Sugar prices fell. "Investors are still reluctant to take long term positions in sugar as fundamentals remain bearish on the prospect of a large global surplus for this season," Davies noted.

By Friday on the LIFFE, the price per tonne of white sugar for August delivery eased to 334 dollars, from 340 dollars a week earlier.

On the NYBOT, the price of unrefined sugar for July delivery slid to 9.25 US cents a pound, from 9.29 cents.

Grains and soya: Grains and soya prices rose as traders said that hot weather in key producers had cut crop output.

By Friday on the Chicago Board of Trade, the price of maize for July delivery jumped to 3.91 dollars a bushel, from 3.76 dollars a week earlier.

Wheat for July delivery climbed to 5.27 dollars a bushel, from 5.01 dollars.

July-dated soyabean meal -- used in animal feed -- increased to 8.14 dollars, from 8.13 dollars.

On the LIFFE, London's futures exchange, the price per tonne of wheat for November delivery increased to 103.80 pounds, from 102.75 pounds the previous week.