U.S. stock index futures slid sharply on Wednesday, with Nasdaq futures touching a four-week low after President Donald Trump said a memorandum of ‌understanding aimed at ⁠ending ⁠the war with Iran was "over", sending oil prices rising.Speaking in Ankara ahead of a ​NATO summit in the Turkish capital, the U.S. president said he had no interest ​in engaging further with Iran, deepening investor concerns over renewed escalation in the Middle East and marking the latest blow to the fragile ceasefire ​between Washington and Tehran.Iran's Revolutionary Guards said ⁠they had ‌targeted U.S. military sites in Bahrain and Kuwait after ​the U.S. ​launched a wave of strikes on Iran. Washington said those ⁠strikes were in response to attacks on tankers in ​the Strait of Hormuz, a critical waterway for global ​oil shipments.Oil prices extended gains on Wednesday following Trump's remarks, with Brent crude futures and U.S. West Texas Intermediate crude futures both rising more than 5%.The jump in crude prices lifted energy stocks in premarket trading. Chevron rose 2.4%, Exxon Mobil gained 3% and ConocoPhillips advanced ‌2.2%.Devon Energy climbed 2.5%, while Occidental Petroleum, APA Corp and Diamondback Energy were up 2.6%, 4.2% and 2.4%, respectively.Investors will ​also focus ​on the minutes ⁠of the U.S. Federal Reserve's June policy meeting, due later in the session, for clues on how policymakers are assessing inflation risks and economic growth.According to ​CME's FedWatch tool, markets are currently pricing in at least one rate hike by the end of 2026.At 04:56 a.m. ET, Dow E-minis fell 620 points, or 1.17%, S&P 500 E-minis lost 63.75 points, or 0.84%, and Nasdaq 100 E-minis shed 330 points, or 1.12%.