ROME — It seems there is a conflict with “deconfliction.” So, hello, “basic technical discussions.”

The Obama administration on Wednesday rejected the notion that the United States and Russia were coordinating their side-by-side military campaigns in Syria, as American officials took pains to distance themselves from a combined ground and air offensive undertaken by the Syrian government and backed by Russian warplanes.

Defense Secretary Ashton B. Carter sharply took issue with suggestions, particularly in the Arab world, that the United States was cooperating with Russia, and he insisted that the only exchanges that the Pentagon and the Russian military could have on Syria at the moment were technical talks on how to steer clear of each other in the skies above the country.

All last week, senior defense officials had described such discussions as “deconfliction” talks, but on Wednesday, as Russian jets pounded groups opposed to Syria’s president, Bashar al-Assad, and as Mr. Assad’s government embarked on a ground offensive, Mr. Carter downgraded even the semantics used to describe any Russian and American information-sharing.