Investing.com-- U.S. stock index futures fell on Sunday evening, with Wall Street remaining weak after concerns over the war on Iran sparked four straight weeks of losses.

S&P 500 Futures fell 0.3% to 6,542.25 points by 19:50 ET (23:50 GMT). Nasdaq 100 Futures fell nearly 0.4% to 24,008.0 points, while Dow Jones Futures fell 0.16% to 45,821.0 points.

Trump issues 48-hr deadline on Iran to reopen Strait of Hormuz

Markets grew wary of an escalation in the conflict after President Donald Trump issued a 48-hour deadline for Iran to reopen the Strait of Hormuz, or else the U.S. would "obliterate" key energy infrastructure in the country.

Iran responded by threatening to attack critical energy and water infrastructure across the Middle East, and also warned it would completely shut the strait.

Hormuz is a key shipping lane that supplies roughly 20% of the world’s oil and gas consumption. Iran has kept the strait largely closed since the beginning of U.S. and Israeli aggression against the country in late-February.

Oil prices rose sharply on the conflict, sparking concerns over heightened energy-fueled inflation, which could in turn keep major global central banks hawkish in the coming months.

A slew of major central banks signaled last week that they were prepared to raise interest rates to offset an oil-fueled surge in inflation. The Federal Reserve also offered a hawkish outlook, but stopped short of signaling rate hikes.

Reports on Sunday evening pointed to little de-escalation in the conflict, which entered its fourth consecutive week.

Wall St nurses four weeks of losses as Iran war rages on

Wall Street indexes were nursing four straight weeks of losses as concerns over the long-term economic impact of a prolonged war with Iran spurred broad moves out of risk-driven assets.

The S&P 500 slid 1.5% on Friday, while the NASDAQ Composite and Dow Jones Industrial Average fell 2% and 1%, respectively.

All three indexes were down between 4% and 7% in the last 30 days.

Beyond the war, stronger-than-expected U.S. inflation data also weighed on Wall Street, as they added to concerns over fewer rate cuts by the Fed this year.