STORY: Wall Street's main stock indexes ended lower after a volatile session on Tuesday, with the Dow dropping almost two-tenths of a percent, the S&P 500 shedding nearly four-tenths of a percent and the Nasdaq losing more than eight-tenths of a percent.

Investors swayed between fears of rising oil prices and hopes for a resolution to the U.S.-Israeli war on Iran.

"Well, the ugly word of uncertainty is back."

Robert Conzo is CEO and managing director of The Wealth Alliance.

"It's back in a big way. And you're seeing it come out in many different markets in many different ways. And why is it? Because volatility amongst many different data points is at a real high. And it all starts with the one that you've heard - oil, oil, and more oil."

Crude oil futures settled up more than 4% as reports suggested that more American troops were headed to the Middle East and with Iran contradicting President Donald Trump's claim that it had held talks with the U.S. to end the war.

Among the 11 S&P 500 major industry sectors, energy led gains during the session while communication services and technology led losses.

Among individual movers, shares of Jefferies rose 2.5% after the Financial Times reported that Japan's Sumitomo Mitsui Financial Group is working on plans for a possible takeover of the investment bank.

And shares of cosmetics maker Estee Lauder tumbled nearly 10% after the company said it was in talks for a potential merger with Spanish beauty group Puig Brands.