Talks began Wednesday in Geneva, Switzerland, with high-ranking officials from six major powers, The New York Times reported.
On Tuesday, the White House spelled out its position, saying the talks amount to an "opportunity to halt the progress of the Iranian [nuclear] program and roll it back in key respects."
The talks are expected to end Friday. Until then, traders may be betting on rhetoric.
Iran's Ayatollah Ali Khamenei said he would not "interfere in the details of the talks." On the other hand, he said "that we will not step back one iota from our rights" to create its own nuclear enrichment program.
On the New York Mercantile Exchange, West Texas Intermediate, light, sweet crude gave up 4 cents to reach $93.30 per barrel. Reformulated gasoline shed 1.61 cents to reach $2.6234 a gallon.
Home heating oil added 0.76 cents to hit $2.9125 gallon.
Natural gas gained 5 cents to $3.60 per million British thermal units.
At the pump, the national average price of unleaded gasoline rose for the second consecutive day, climbing to $3.212 per gallon from Tuesday's $3.209, the AAA Daily Fuel Gauge Report said.