Wall Street futures pointed lower pre-bell Wednesday after days of Iranian attacks on commercial vessels in the contested Strait of Hormuz, followed by President Donald Trump's statement on Tuesday that the Persian Gulf ceasefire was "over."

The vital sea passageway Strait of Hormuz is again apparently closed, as Iran and the US trade military attacks.

In the futures, the S&P 500 fell 0.8%, the Nasdaq declined 1.2% and the Dow Jones was off 1.1%.

West Texas Intermediate crude oil traded up 4.9% to $73.88 in morning hours.

Investors also await the 2 pm ET release of minutes of the Federal Reserve's June 16-17 policy session, the first chaired by Kevin Warsh, for clues to central bank thinking.

Asian exchanges traded unevenly lower overnight, while European bourses tracked sharply south midday on the continent.

Levi Strauss (LEVI) plans to report earnings pre-bell, among others.

On the economic calendar, in addition to the Federal Reserve minutes, is the weekly EIA petroleum status report at 10:30 am ET.

In pre-market action, bitcoin traded at $62,048, and 10-year US Treasuries offered 4.58%. Spot gold commanded $4,055 an ounce.