US stocks end lower on Ukraine worries, S&P 500 -1.9%

Wall Street stocks finished decisively lower Friday as investors reduced risky bets after White House officials warned a Russian invasion of Ukraine could be imminent.

The Dow Jones Industrial Average dropped 1.4 per cent, or more than 500 points, to 34,738.06.

The broad-based S&P 500 dropped 1.9 per cent to 4,418.64, while the tech-rich Nasdaq Composite Index tumbled 2.8 per cent to 13,791.15.

Markets lurched during a briefing by US National Security Advisor Jake Sullivan, who said a Russian invasion could "begin at any time," including during the ongoing Beijing Winter Olympics.

Investors had become less worried about an imminent invasion of Ukraine in recent days following Western diplomacy with Russian President Vladimir Putin, said Art Hogan, chief strategist at National Securities.

But the shift in tone Friday from the Biden administration prompted a sell-off ahead of the weekend market closure, pushing all three major indices into the red for the week.

"If the market hasn't fully priced in the risk of a Russian incursion into Ukraine, it may start to do that," said Hogan, adding that markets were in a "risk-off" mode.

Besides Ukraine, investors have also been nervous over the pivot in monetary policy from the Federal Reserve and other central banks anxious to counter inflation.

Offsetting that negative has been a wave of mostly solid corporate earnings. On Friday, most industrial sectors finished lower.

An exception was energy, with oil giants Chevron and ExxonMobil winning more than two per cent on higher crude prices in the wake of Ukraine uncertainty.

Shares of weapons makers also moved higher, including Lockheed Martin, which gained 2.8 per cent and Northrop Grumman, which rose 4.5 per cent.