International oil prices climbed above the $100 a barrel mark early Wednesday for the first time since July as U.S.-Iran fighting intensified. Treasury yields were creeping higher amid the inflation pressure of higher energy costs.

Brent crude, the international standard, was up 2.9% at $100.78 a barrel. West Texas Intermediate, the U.S. standard, was rising 2.8% to $95.63 a barrel.

The U.S. military destroyed five Iranian oil tankers Tuesday in retaliation for Iran's attempts to strike American warships in the Middle East, The Wall Street Journal reported. Iran retaliated overnight with a ballistic-missile attack into Jordan.

Meanwhile, a Houthi military spokesman said Tuesday on social media that the Iran-backed militant group launched dozens of ballistic missiles and drones at Saudi Aramco facilities.

UBS analysts raised their forecast for Brent oil prices, expecting the crude benchmark to trade at $95 a barrel at the end of the year, from $85 previously.

"The overnight strikes on energy facilities in Saudi Arabia or threats by Iranian officials suggest risks for oil prices will remain to the upside for now, in our view," UBS strategist Giovanni Staunovo wrote in a research note. "Continued strikes on vessels attempting to transit the Strait of Hormuz via the southern lane, despite U.S. military escorts, leave flows vulnerable to renewed disruption."

The benchmark 10-year Treasury yield ticked up to 4.811% early Wednesday. The key anticipated driver of U.S. debt yields this week will be Friday's consumer price index reading, ahead of the Federal Reserve's rate decision on Sept. 16.