Gold futures on the COMEX division of the New York Mercantile Exchange lost more than one percent on Friday due to massive selling activities.

The most active gold contract for December delivery fell 13.30 dollars, or 1.03 percent, to settle at 1274.20 dollars per ounce. It's the biggest one-day loss in more than three weeks.

The sharp fall was triggered by a series of massive sales which moved about four million ounces of gold in the futures market towards the end of the session, said financial observers.

The sell-off led to the sudden drop of gold prices in about 10 to 15 minutes.

Analysts can hardly explain the reason behind what they call the "mysterious" sell-off, even when both New York stocks and the U.S. dollar continued to retreat, as they usually move inversely to precious metals.

The U.S. dollar index, a measure of the dollar against a basket of other major currencies, fell 0.13 percent to reach 94.41 as of 1810 GMT.

Meanwhile, the Dow Jones Industrial Average lost 56.27 points, or 0.24 percent, to 23,405.67 as of 1821 GMT.

As for other precious metals on Friday, silver for December delivery fell 10.4 cents, or 0.61 percent, to close at 16.871 dollars per ounce. Platinum for next January went down 8.50 dollars, or 0.90 percent, to settle at 932.10 dollars per ounce.