Gold futures on the COMEX Division of the New York Mercantile Exchange further hiked on Thursday, extending the metal's rally into the fourth trading day, as a weaker euro spurred buying of gold.The most active gold contract for February delivery climbed 7.4 U.S. dollars, or 0.5 percent, to 1,620.1 dollars per ounce, the highest settlement since Dec. 13.Market analysts said that the biggest influence was the weakening euro, which prompted investors to flee the euro and bought gold. The euro fell under 1.28 against dollar on Thursday as investors focused on concerns about euro zone banks and a French bond sale that was met by cold reception.Moreover, gold gained strength from safe-haven demands after British Defence Secretary said the country may take military action if Iran carries out its threat to block the Strait of Hormuz.A trader noted that Iran is gradually becoming a big source of concern and people are worried what could happen next.The four-day advance, which marks the longest rally in 10 weeks, has added 5.2 percent to gold prices.Silver for March delivery rose 19.9 U.S. cents, or 0.68 percent, to 29.296 dollars per ounce. Platinum for April delivery dropped 8. 3 dollars, or 0.58 percent, to 1,418 dollars per ounce.