Gold futures on the COMEX division of the New York Mercantile Exchange tallied a third-straight gain Wednesday, maintaining their short-term boost from political uncertainty in the U.S., as the Federal Reserve Chair Janet Yellen reiterated a call for 'gradual' interest-rate hikes in Capitol Hill testimony.

The most active gold contract for August delivery rose 4.4 U.S. dollars, or 0.36 percent, to settle at 1,219.10 dollars per ounce.

Analysts said the precious metal has found support as a haven investment amid turmoil in the White House following Donald Trump Jr.'s release of emails linked to a meeting with a Russian Lawyer last year.

In testimony on Capitol Hill Wednesday, Yellen said the Fed "continues to expect that the evolution of the economy will warrant gradual increases in the federal funds rate over time..."

As for other precious metals, silver for September delivery added 14.2 cents, or 0.9 percent, to close at 15.887 dollars per ounce. Platinum for October delivery rose 20.30 dollars, or 2.26 percent, to close at 919 dollars per ounce.