U.S. stock futures crept down while oil prices continued to surge, as investors monitored Russia’s invasion of Ukraine and how a jump in commodities prices is likely to impact inflation and the Federal Reserve’s monetary policy.

Futures for the S&P 500 edged down 0.1% Thursday. The broad-market index shot up Wednesday. Contracts for the tech-focused Nasdaq-100 declined 0.4% and futures for the Dow Jones Industrial Average fell 0.2% Thursday.

Crude prices surged over $115 a barrel for the first time since 2008, as refiners balked at buying Russian oil, reducing the global energy supply. Brent-crude futures, the international benchmark, rose 3.5% to $116.93 a barrel. Investors are worried that a prolonged elevation in oil prices could precede a combination of slowing growth and higher inflation, known as stagflation.

“The inflationary impact of oil and natural gas surges is clear. Inflation is going to be stickier. Interests rates will be pushed up by central banks worried about inflation and that will be bad for growth,” said Edward Park, chief investment officer at U.K. investment firm Brooks Macdonald. “Stagflation is the big concern for 2023.”

European natural-gas prices rose 8%, adding to a surge this week. Investors are worried that supply of natural gas could be disrupted to Europe as a result of the war. About a third of Russian gas exports to Europe flow through Ukraine, according to analysts.

The pan-continental Stoxx Europe 600 fell 0.2% Thursday. Russian stock markets remained closed for the fourth consecutive day as the government seeks to limit a firesale, having also imposed capital controls on the ruble.

The London Stock Exchange Group has suspended trading in more than 50 Russian stocks. Index providers MSCI Inc. and FTSE Russell have said they will cut Russian equities from their benchmarks next week and S&P Dow Jones Indices is considering doing the same.

The ruble dropped 11.6% Thursday against the greenback to 116 rubles to the dollar, according to FactSet. Traders say investors’ and brokers’ unwillingness to touch the currency has limited the ease with which they can trade it. Currencies of nearby countries have fallen against the dollar as well, as investors worry about economic spillover. The Polish zloty fell 0.8% Thursday, and the Hungarian forint declined 0.7%.