Oil prices fell from their daily highs after President Trump posted on social media that the U.S. is having "productive discussions" with Iran and won't attack the country prior to the midterm elections.

Benchmark Brent crude prices are still up around 3.5% on the day however and are heading for their highest close since mid-September. The price had risen more than 5% earlier, pushed up in part by a fresh tanker attack in the Persian Gulf.

Rising energy prices are weighing on U.S. stocks, which are slipping for a second day. The Nasdaq composite is down about 0.5%, leading indexes lower.

The U.S. had recently succeeded in restoring crude shipments through the Strait of Hormuz, but Iran appears to have intensified its attacks on tankers in response, putting oil markets on edge. Production cuts in the Gulf of Mexico, prompted by a hurricane, aren't helping either.

Benchmark Treasury yields were lower, ticking down after the Trump post on Truth Social. Some investors also saw opportunity in buying at higher yields yesterday, when a strong 10-year Treasury auction soothed some market fears.