(Updates with index/price moves and political news from the first paragraph.)

US equity indexes slumped while volatility surged with crude oil and government bond yields after President Donald Trump warned of more strikes on Iran after saying a peace deal signed in June "is over"

The Dow Jones Industrial Average dropped 1.5% to 52,107.8, with the Nasdaq Composite down 1% to 25,572.5, and the S&P 500 lower by 1% to 7,434.1 after midday Wednesday.

Energy was the standout gainer, with Valero Energy (VLO), Occidental Petroleum (OXY), and Phillips 66 (PSX) leading the S&P 500. Chevron (CVX) was the Dow's top gainer. On Nasdaq, the top spot went to Baker Hughes (BKR).

The CBOE Volatility Index jumped 13% to 18.18 after Trump said, per a Bloomberg report, the US would probably launch further strikes on Iran and could resume a blockade on the country's ports.

"We hit them very hard last night," Trump said Wednesday on the sidelines of a summit of the North Atlantic Treaty Organization leaders in Ankara, Turkey. "Probably hit them hard again tonight."

The front-month global benchmark North Sea Brent soared 7% to $79.37 a barrel, and the US West Texas Intermediate surged 6.9% to $75.29 a barrel.

US Treasury yields rose, with the two-year yield jumping 5.8 basis points to $4.22% and the 10-year climbing 6.2 basis points to 4.59%.