NEW YORK – The stock market sagged Monday after the Obama administration ratcheted up pressure against Syria.

Secretary of State John Kerry said there was "undeniable" evidence of a large-scale chemical weapons attack in Syria last week, and his remarks suggested that the administration was edging closer to a military response.

Major indexes had been holding on to slight gains on Monday until the last hour of trading, when Kerry's televised talk appeared to jolt it lower, said Stephen J. Carl, head equity trader at the Williams Capital Group.

The S&P 500 index ended with a loss of 6.72 points, or 0.4 percent, at 1,656.78. The index was up two points just before Kerry began reading his statement.

The Dow Jones industrial average fell 64.05 points, or 0.4 percent, to close at 14,946.46. The Nasdaq composite slipped 0.22 of a point, or 0.01 percent, to 3,657.57.

A handful of corporate deals gave the market a lift in the early going. Amgen surged following its announcement late Sunday that the biotech giant plans to buy Onyx Pharmaceuticals for $10.4 billion.

The Federal Reserve will start a two-day meeting Sept. 17, during which officials will discuss phasing out support for the economy. After that, Germany holds national elections that could change how the region handles rescue loans for troubled countries. The U.S. Congress returns from its summer break next week and will take up a new budget before the fiscal year starts on Oct. 1.

"These issues are big enough to transcend daily data," Ablin said.

The market is expected stay quiet this week, when many traders typically take a summer break before returning after Labor Day.

ASSOCIATED PRESS