* U.S. third-quarter GDP data better-than-expected
* Palladium touches 16-week low
* Platinum on track for biggest weekly rise in three months (Updates prices; adds comment, second byline, NEW YORK dateline)
By Marcy Nicholson and Zandi Shabalala
NEW YORK/LONDON, Oct 28 (Reuters) - Gold rose 1 percent to the highest level in nearly four weeks on Friday, extending gains late in the session after the FBI said it will further investigate Democratic presidential candidate Hillary Clinton's use of a private email system.
Just 11 days ahead of the U.S. presidential election, the news shook up the campaign, in which Clinton is the front-runner in opinion polls. gold XAU= was up 0.8 percent at $1,278.38 an ounce by 2:54 p.m. EDT (1854 GMT), after rising 1.3 percent to $1,284.14, the highest since Oct. 4. It is on track to close the week up 0.9 percent.
U.S. gold futures GCcv1 settled up 0.6 percent at $1,276.80.
"The FBI headlines startled a somnolent gold market, driving bullion a percent higher in a hour on concerns that a late October surprise could suddenly bolster (Donald) Trump's sagging fortunes," said Tai Wong, director of base and precious metals trading for BMO Capital Markets in New York.
"The rally may not last, though, as we are at the two-minute warning and Clinton is ahead by two scores, so it would require a truly shocking revelation to derail her chances."
Wall Street and the dollar .DXY fell against a basket of six major currencies after the Federal Bureau of Investigation said it would probe additional emails related to Clinton while she was secretary of state. MKTS/GLOB
The greenback was already weak, having shrugged off slightly better-than-expected U.S. third-quarter GDP data amid firm demand from Asia.
The U.S. economy grew by 2.9 percent in the third quarter, outpacing analysts' consensus forecast of 2.5 percent. The data strengthened the case for an interest rate increase, making non-yielding assets such as gold less attractive while boosting the dollar and U.S. treasuries.
Demand for bullion in India is expected to pick up during the Dhanteras and Diwali festivals, when gold is traditionally given as a gift.
In other precious metals trading, silver XAG= gained 1.3 percent at $17.82 an ounce and platinum XPT= rose as much as 2.6 percent to $987, the highest since Oct. 5.
Silver was on track for its biggest weekly gain in five, while platinum was heading toward its best week in three months.
A Reuters poll on Friday showed platinum prices are expected to rise next year to their highest since 2014 on an average basis, but will remain at a discount to gold. XPD= rose 1.4 percent at $618.35, switching direction after tapping a 16-week low of $608.47.