* Prices gain as retail sales data come in weaker than expected * White House denies report of Summers Fed appointment * Fed to buy $3 billion to $4 billion in notes due 2019, 2020 By Karen Brettell NEW YORK, Sept 13 (Reuters) - U.S. Treasuries yields fell on Friday after data showed that U.S. retail sales rose less than expected in August, pointing to slower growth before the Federal Reserve's highly anticipated meeting next week, where it is expected to announce it will reduce its bond purchases. The White House, reacting to a report in a Japanese newspaper that Lawrence Summers would soon be named to head the Federal Reserve, said no decision had been made yet, adding a bid to bonds which were earlier hurt by the report. Summers is viewed as being more hawkish than Fed Vice Chair Janet Yellen, who is also seen as a leading contender for the job, and as such more likely to raise interest rates at a faster pace. The retail sales data is seen as the last significant economic release before the Fed meets next Tuesday and Wednesday. The U.S. central bank will release a policy statement on Wednesday after its two-day meeting. "Retail sales were weaker than expected," said Sean Murphy, a Treasuries trader at Societe Generale in New York. The Commerce Department said that retail sales increased 0.2 percent last month as Americans bought automobiles, furniture and electronics and appliances. However, they cut back on clothing, building materials and sporting goods. U.S. producer prices also rose in August by 0.3 percent as energy costs rebounded, but underlying inflation remained tame. The data is seen as unlikely to sway the Fed from tapering its $85-billion-a-month bond purchase program. "Bonds should tread water here, the bigger event will be next week's FOMC meeting where we're looking for the Fed to announce their tapering plans somewhere in the area of $10 billion-a-month reduction," said Murphy. The Fed will buy between $3 billion and $4 billion in notes due 2019 and 2020 on Friday as part of its ongoing purchase program. U.S. benchmark 10-year Treasury notes were last up 5/32 in price to yield 2.89 percent, down from 2.91 percent late on Thursday. They have fallen from a two-year high of 3.01 percent last Friday. Thirty-year bonds rose 16/32 in price to yield 3.83 percent, down from 3.85 percent on Thursday. Bonds have also gained a bid after the Treasury completed the sale of $65 billion in new debt to strong demand, in part because investors unlocked hedges placed ahead of Verizon's record-breaking $49 billion bond sale on Wednesday.