NEW YORK - After opening sharply lower as Russia launched a special military operation in Ukraine and the United States and Europe threatened massive sanctions, Wall Street indices ended trading in positive territory Thursday.

The broad-based S&P 500 was up 1.5 percent at 4,288.70 at the close, while the tech-rich Nasdaq Composite Index climbed 3.3 percent to finish at 13,473.59.

The benchmark Dow Jones Industrial Average gained 0.3 percent to end at 33,223.83.

It was unclear if Moscow would retaliate with steps like curbing their energy exports, which could drive up fuel prices as many nations deal with high inflation, but Tom Cahill of Ventura Wealth Management said US markets had overdone their selling and were due for gains.

"We were definitely oversold and due for a bounce," he said. "I think there was a 'buy the rumor, sell the news' waiting to happen, and... it kind of fed on itself."

The gains capped a session that began on a starkly different note, with the Dow 2.2 percent in the red minutes into trading and the Nasdaq 2.5 percent underwater.

Tech stocks were among the big gainers as traders hunted for deals, with Netflix climbing 6.1 percent by the close, Microsoft winning 5.1 percent and Meta Platforms, formerly Facebook, gaining 4.6 percent.

AFP