* Yellen says Fed on course to raise rates at an upcoming meeting
* U.S. dollar index hits three-week highs
* SPDR Gold holdings up 0.49 percent (Adds comment, byline, NEW YORK dateline; updates prices)
By Marcy Nicholson and Maytaal Angel
NEW YORK/LONDON, Feb 14 (Reuters) - Gold came off its highs on Tuesday, as the dollar advanced after U.S. Federal Reserve Chair Janet Yellen said the central bank will likely need to raise interest rates at an upcoming meeting with the economy expanding further.
The Federal Reserve chair struck a more hawkish tone than investors had expected, although she did flag considerable uncertainty over economic policy under the new administration.
U.S. President Donald Trump's national security adviser Michael Flynn resigned on Tuesday over revelations that he had discussed U.S. sanctions against Moscow with the Russian ambassador before Trump took office. gold XAU= traded 0.4 percent higher at $1,229.49 an ounce by 2:36 p.m. EST (1936 GMT), while U.S. gold futures GCcv1 settled down 0.03 percent at $1,225.40.
The dollar index .DXY reached the highest in more than three weeks following Yellen's prepared remarks before the Senate Banking Committee, while Wall Street rose to a record. MKTS/GLOB
"Yellen is trying to nudge the expectations for a rate hike in March higher. This doesn't mean they will move in March, but the Fed wants to have the option to move," said Omer Esiner, chief market strategist at Commonwealth Foreign Exchange Inc.
Gold is highly sensitive to rising U.S. interest rates, which increase the opportunity cost of holding non-yielding bullion while boosting the dollar, in which it is priced.
"There's a nod to further tightening ahead and the risks of waiting too long, and there is a reference to the need at upcoming meetings to evaluate if the economy is evolving in a way that makes further hikes appropriate," said Avery Shenfeld, chief economist for CIBC Capital Markets in Toronto.
"Note the use of the plural on 'meetings,' so there was no specific allusion to a March hike in the statement, and Yellen also emphasized that any hikes will be 'gradual.'"
Ahead of the testimony, Richmond Fed President Jeffrey Lacker said the U.S. central bank will likely have to raise rates faster than financial markets currently expect given any new policies by the Trump administration, while uncertain, will force the central bank's hand. the upside for gold, holdings of SPDR Gold Trust GLD , the world's largest gold-backed exchange-traded fund, rose 0.49 percent to 840.87 tonnes on Monday. GOL/ETF
Gold has rallied nearly 10 percent since touching 10-month lows in December.
In other precious metals, spot silver XAG= rose 1 percent to $17.97, having hit its highest since Nov. 11 above $18 earlier.
Palladium XPD= gained 1 percent to $782.40 while platinum XPT= was up 0.6 percent at $1,001.20.
"Platinum also saw noticeable ETF inflows of 8,900 ounces (Monday)," Commerzbank (DE:CBKG) said in a note.