By Noel Randewich

(Reuters) - Energy stocks spiked while the rest of Wall Street fell on Monday after weekend attacks on Saudi Arabia's oil facilities added to investors' concerns about geopolitical risk and a slowing global economy.

The attacks on the world's biggest crude exporter sent oil prices up more than 20% before they eased as various nations said they would tap emergency reserves to ensure stable supplies.

The S&P 500 energy <.SPNY>, one of the worst performing sectors so far this year, soared 3.75%, on track for its largest one-day gain since December. Shares of Apache Corp <APA.N>, Marathon Oil Corp <MRO.O> and Helmerich and Payne <HP.N> jumped between 12% and 18% and were the leading gainers on the S&P 500.

The Saudi-led military coalition battling Yemen's Houthi movement said the attack was carried out with Iranian weapons, raising the prospect of a global conflict involving the United States and Iran.

"The U.S. investor is waiting with bated breath about what the U.S. and its allies might do," said Jake Dollarhide, chief executive officer of Longbow Asset Management in Tulsa, Oklahoma.

Anticipation of higher fuel costs drove down shares of airlines and cruise line operators with the S&P 1500 airlines <.SPCOMALI> shedding 2.5%, while Carnival Corp <CCL.N> fell 3.7%.

Retail stocks <.SPXRT> lost 1.5% and were among the biggest drags on the S&P 500.

"The drone strike in Saudi has had an impact on how investors are looking at the security and stability of the global energy supply chain and is fuelling a degree of risk reassessment," said Peter Kenny, founder of Kenny's Commentary LLC and Strategic Board Solutions LLC in New York.

Shares of defence companies Raytheon <RTN.N>, Lockheed Martin Corp <LMT.N>, Northrop Grumman Corp <NOC.N> rose more than 1%. J.P. Morgan upgraded Raytheon shares to "overweight."

At 2:27 p.m. ET, the Dow Jones Industrial Average <.DJI> was down 0.44% at 27,098.81 points, while the S&P 500 <.SPX> lost 0.31% to 2,998.13.

The Nasdaq Composite <.IXIC> dropped 0.28% to 8,153.98.

Nine of the 11 major S&P sectors were lower.

Wall Street's more than a decade-long rally continues to hinge on whether the Fed will keep cutting interest rates and on progress in U.S.-China trade talks. A recent easing in trade tensions has brought the benchmark S&P 500 <.SPX> about 1% below its record high.

Among other movers, General Motors Co <GM.N> fell 4.7% after the United Auto Workers went on strike on Sunday, the first nationwide strike at GM in 12 years.

Advancing issues outnumbered declining ones on the NYSE by a 1.14-to-1 ratio; on Nasdaq, a 1.24-to-1 ratio favoured advancers.

The S&P 500 posted 5 new 52-week highs and 1 new low; the Nasdaq Composite recorded 47 new highs and 24 new lows.

(Additional reporting by Medha Singh and Ambar Warrick in Bengaluru; Editing by Nick Zieminski)