Gold futures rebounded above the $1,600 mark Friday as investor demand for a refuge was heightened by the slow progress toward an agreement to raise the US debt ceiling. Gold for August delivery, the most actively traded contract, climbed $14.50, or 0.9 percent, to settle at $1,601.50 a troy ounce on the Comex division of the New York Mercantile Exchange, just short of the record settlement of $1,602.40 reached Monday. “There's still uncertainty with no (US debt) agreement,” said Frank McGhee, a broker with Integrated Brokerage Services. “There is still the potential for a short-term default.” Some investors turn to gold as a safe haven during turmoil in other markets, and futures have climbed sharply this month as investors piled into it amid worries that sovereign debt on both sides of the Atlantic could zap assets such as stocks or bonds. Concern about a potential default by a euro-zone member eased after Thursday's deal to restructure the European currency union's rescue fund and provide another round of support for debt-laden Greece. But talks on raising the US debt ceiling haven't reached a similar resolution.