U.S. futures slipped, with the futures for the S&P 500 and Dow Jones Industrial Average down 0.3%.
In early European trading, Britain's FTSE 100 fell 0.7% to 10,235.29. Germany's DAX lost 1% to 23,345.90, while France's CAC 40 dropped 1.2% to 7,887.18.
In Asian trading, Tokyo’s Nikkei 225 index slipped 1.2% to 53,819.61. Technology-related stocks saw some of the bigger losses, with SoftBank Group falling 4.5%.
Oil prices held steady as Brent crude, the international standard, traded at $101 per barrel. Benchmark U.S. crude was up 0.5% at $96.23 per barrel.
Oil prices have been volatile since the Iran war began. While the International Energy Agency said Wednesday its members would make a record 400 million barrels of oil available from their emergency reserves. President Trump also announced that he will dip into the U.S. Strategic Reserve to help alleviate oil prices.
Wall Street recorded losses Thursday following volatile swings this month. The S&P 500 dropped 1.5% and the Dow Jones Industrial Average fell 1.6%. The Nasdaq composite shed 1.8%.