Pentagon casts doubts on Russian claim of killing ISIS leader

The US has no information that supports Russia's claim that it killed senior ISIS leader and spokesman Mohammad al-Adnani, the Pentagon has said.

The Russian claim came a day after Pentagon said it carried out a precision attack against Adnani in Syria's Al Bab region. ISIS had announced his death through its media outlet Amaq.

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.

"So his elimination would be a significant blow to ISIL, its leadership, and importantly, a significant step in reducing ISIL's ability to conduct external attacks outside of Iraq and Syria," he 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.