US says it is still assessing the assessing the results of the airstrike.
"We have no information to support Russia's claim that it carried out a strike against Adnani," Pentagon Press Secretary Peter Cook told reporters at a news conference.
Russia, has spent most of its military campaign supporting and propping up the Assad regime, Cook said.
"It has not devoted much, if any, effort that we're aware of targeting ISIL's leadership. And at the same time, we have not seen the Russian military campaign use precision weaponry on a regular basis as well," he said.
Cook said Adnani has been responsible for the Islamic State's external terror strategies. He is "directly responsible" for recruiting foreign fighters and encouraging attacks against the West, Cook said.
The US had been actively been looking for Adnani for some time, given his prominent role within the organisation.
"I'm not going to get into intelligence or operational matters, but we have already confirmed for you all that we conducted a precision strike yesterday targeting Adnani near al-Bab, Syria. We are still assessing the results of that strike," he said.