As the yearslong Russia-Ukraine war intensifies, experts say some key components of the modern economy could be at risk, and markets are still guessing as to what the conflict could bring next.

On Sunday, President Biden gave Ukraine permission to use U.S.-made long-range missiles to strike deep into Russian territory, a move marking a stark reversal from the administration a mere two months before leaving office. Ukraine quickly seized on the newfound permission to strike a facility in the Bryansk region Tuesday using U.S.-made missiles, Russia’s Defense Ministry said. In response, Russian President Vladimir Putin lowered the country’s threshold for using nuclear weapons, a clear warning to the West.

Due in part to the escalating aggression, all three major indexes fell early Tuesday, with the Dow dropping about 450 points and the S&P 500 dropping 0.5% soon after market open. Yet, by the end of the day, markets were mixed, with the Nasdaq jumping 1%, fueled in part by Nvidia earnings, and the S&P notching a 0.3% advance. Meanwhile, the Dow fell about 0.3%, or 120.66 points.

Fueling the market whipsaw was the uncertainty of Russia’s response to Ukraine’s latest strike, economist Aleksandar Tomic, the associate dean for strategy, innovation, & technology at Boston College’s Woods College of Advancing Studies, told Fortune.

While stocks have been on the upswing in recent weeks since President-elect Donald Trump won the White House, there has been some volatility recently, said Tomic, and geopolitical issues are adding to the uncertainty.

“The Ukrainians did what they did, now, the question is, what do the Russians do to retaliate,” Tomic said. “And I think what it is, is that nobody knows, so that breeds uncertainty, and then markets react to uncertainty.”

Another way that an escalated conflict in Ukraine could affect markets is through the threat to natural resources that make up semiconductors, which are already facing a shortage, said Usha Haley, an international business professor at Wichita State University. Key components of semiconductors, such as Palladium and Neon are found either in Russia or Ukraine, Haley told Fortune.

“Semiconductors are central to many US industries, so these shortages and resulting production delays will likely have broad economic impact through supply chains and lead to more inflation,” Haley said.

Still, Tomic said the risk of the Russia-Ukraine war having a major impact on markets is likely overblown because investors have already priced in the risks during the nearly four-year-long conflict. Other geopolitical concerns such as Trump’s proposed tariffs on imported foreign products are more likely to have an impact, Tomic said.