BlackRock Inc said on Friday it had suspended the issuing of shares in its physically backed gold exchange traded product due to a historic surge in buying as global economic uncertainty rekindled bullion's safe-haven appeal among investors.

While the BlackRock move appears to be an isolated case, it illustrates the voracious demand for bullion as economic uncertainty, a weak dollar and falling expectations for U.S. interest rate hikes have spurred the biggest buying spree of gold ETFs in five years and helped prices rally to their highest in 13 months.