Nov 30 (Reuters) - Wall Street"s main indexes closed lower on Tuesday after Federal Reserve Chair Jerome Powell signaled that the U.S. central bank would consider speeding up its withdrawal of bond purchases as inflation risks increase, piling pressure onto a market already nervous about the latest COVID-19 variant. In a testimony before the Senate Banking Committee, Powell indicated that he no longer considers high inflation as "transitory" and that the Fed would revisit the timeline for scaling back its bond buying program at its next meeting in two weeks. read morePowell"s comments threw a monkey in the wrench in market thinking in terms of potential taper timing. You"re seeing as a result of that, risk-off across the board," said Michael James, managing director of equity trading at Wedbush Securities in Los Angeles. "You also have to factor in the Omicron variant concerns. You can argue whether they"re more headline risk or reality risk but regardless, it"s having a significant impact on oil, and everything that"s tied to economic growth."Powell"s comments also prompted speculation among some investors about a potential acceleration in interest rate hikes. "The principal contributor to the decline in stock prices today is the Powell commentary, regarding the upcoming Fed meeting, about accelerating the tapering of their bond buying program, which obviously leads to the prospect that rate hikes come sooner next year," said Mark Luschini, chief investment strategist at Janney Montgomery Scott in Philadelphia. "That somewhat hawkish shift in tone caught the market flatfooted," Luschini said. Meanwhile, the market was also left waiting for information about how dangerous the Omicron variant might be, the degree to which current vaccinations could offer protection and the additional restrictions governments might have to impose that could hurt the economy, Luschini said. The Dow Jones Industrial Average (.DJI) fell 652.22 points, or 1.86%, to 34,483.72, the S&P 500 (.SPX) lost 88.27 points, or 1.90%, to 4,567 and the Nasdaq Composite (.IXIC) dropped 245.14 points, or 1.55%, to 15,537.69. For the month, the S&P registered a decline of 0.8%, while the Dow dropped 3.7% and the Nasdaq eked out a 0.25% gain. Only seven of the benchmark S&P 500 components gained ground on Tuesday. For the day, all the 11 major S&P industry sectors fell with seven of those sectors falling more than 2%. Communication services (.SPLRCL) lead the losses with a 3% drop followed by Utilities" (.SPLRCU) 2.9% drop. As oil prices tumbled, energy (.SPNY) were under pressure throughout the session, closing down 2.5%. read moreThe top performer was information technology (.SPLRCT), falling just 0.96%, with help from Apple Inc (AAPL.O), which boasted a recording closing high and a 3.2% gain for the day. Tuesday"s decline was a sharp reversal after Monday"s rally in which stocks regained some ground they had lost on Friday when the market sold-off swiftly on news of the virus variant. "The market is clearly in some treacherous waters right now. You"ve had two significant pullbacks out of the last three trading days. This is certainly shaking some of the complacent longs in the market," said Wedbush"s James. While the Food and Drug Administration said it hopes to have information about the effectiveness of current COVID-19 vaccines against Omicron, vaccine companies were divided. BioNTech"s (22UAy.DE) chief executive said the vaccine his company supplies in partnership with Pfizer (PFE.N) will likely offer strong protection from severe illness in variant cases. But Moderna Inc"s (MRNA.O) CEO told the Financial Times that COVID-19 shots are unlikely to be as effective against the new variant as they have been previously. read more Moderna shares fell 4.4% while Regeneron Pharmaceuticals Inc (REGN.O) lost 2.7% after it said its COVID-19 antibody treatment and other similar drugs could be less effective against Omicron. read more Travel and leisure stocks slumped, with the S&P 1500 Hotels, Restaurant and Leisure (.SPCOMHRL) indexes fell more than 2% while the S&P 1500 Airlines (.SPCOMAIR) index lost 0.6%. The small-cap Russell 2000 index (.RUT) fell 1.9%. The virus uncertainty has triggered fresh alarm at a time when supply chain logjams are weighing on economic recovery and central banks globally are contemplating a return to pre-pandemic monetary policy to tackle a surge in inflation. Meanwhile, data showed U.S. consumer confidence slipped in November amid concerns about the rising cost of living and relentless COVID-19 pandemic. read more Declining issues outnumbered advancing ones on the NYSE by a 3.82-to-1 ratio; on Nasdaq, a 2.40-to-1 ratio favored decliners. The S&P 500 posted seven new 52-week highs and 45 new lows; the Nasdaq Composite recorded 28 new highs and 572 new lows. Tuesday registered the highest volume trading session for U.S. exchanges since June with 16.13 billion shares changing hands, compared with the 11.12 billion moving average for the last 20 sessions.