* S&P 500 posts best weekly performance since December
* Pan-European index rises
* Dollar resumes month-long run (Updates with U.S. markets close)
By Lewis Krauskopf
NEW YORK, Nov 20 (Reuters) - Shares in major markets gained on Friday and the euro weakened against the dollar as investors anticipated actions by U.S. and European central banks next month.
The benchmark U.S. S&P 500 posted its best week in almost a year, while Europe's main stock index tallied its strongest week in a month. U.S. Treasuries prices fell, with rising U.S. stock prices reducing the appeal of lower-yielding government debt.
The head of the European Central Bank, Mario Draghi, offered the strongest hint yet that the ECB will unveil fresh stimulus measures at its Dec. 3 meeting.
"Any siren call from a central bank, particularly a systemically important one, about more largesse on the part of that central bank's balance sheet to try to reflate economic activity is sort of a cause-and-effect for why financial assets then accompany in that rally," said Mark Luschini, chief investment strategist at Janney Montgomery Scott in Philadelphia.
Investors in recent days have also increasingly come to expect that the U.S. Federal Reserve will raise interest rates next month, which would be the first rate increase in almost a decade.
The head of the New York Fed, William Dudley, said the Fed should "soon" be ready to raise interest rates as U.S. central bankers grow confident that low inflation will rebound and that employment will remain stable.
"We've seen a nice bounce in stocks as they've digested to the likelihood of a December rate hike," said Kim Rupert, managing director of global fixed-income analysis at Action Economics in San Francisco.
The Dow Jones industrial average .DJI rose 91.06 points, or 0.51 percent, to 17,823.81, the S&P 500 .SPX gained 7.93 points, or 0.38 percent, to 2,089.17 and the Nasdaq Composite .IXIC added 31.28 points, or 0.62 percent, to 5,104.92.
Nike (N:NKE) shares rose 5.5 percent after the sportswear maker unveiled a $12 billion share buy-back program.
The pan-European FTSEurofirst 300 index .FTEU3 climbed 0.2 percent, near three-month highs.
An index of leading global markets .MIWD00000PUS also rose 0.2 percent.
At a press conference in Frankfurt, Draghi addressed the ECB's considerations at its upcoming meeting: "If we decide that the current trajectory of our policy is not sufficient to achieve our objective, we will do what we must to raise inflation as quickly as possible."
His comments put pressure on the euro EUR= , which fell against the dollar after two days of gains. The euro was off 0.8 percent and slipped below $1.07.
"With the ECB easing policy, I would be very surprised if the euro didn't fall through parity," Mark Burgess, chief investment officer at Columbia Threadneedle Investments, told the Reuters Global Investment Outlook Summit on Friday.
The dollar .DXY rose 0.6 percent against a basket of currencies, resuming its march upward over the past month.
Benchmark 10-year U.S. Treasuries US10YT=RR were down 5/32 in price to yield 2.264 percent, while the 30-year bond US30YT=RR was down 11/32 in price to yield 3.021 percent.
Brent oil futures LCOc1 settled up 48 cents at $44.66 a barrel, helped by short-covering. U.S. crude CLc1 fell nearly 4 percent to below $39, before recovering to settle down 15 cents at $40.39 a barrel.
Spot gold fell 0.4 percent, ending a two-day bounce and up from the lowest level in nearly six years.