US Secretary of State John Kerry said in a TV interview that aired Sunday he is "extremely encouraged" that his country's allies have expressed a willingness to offer military assistance in the fight against Islamic extremists.

"I can tell you right here and now that we have countries in this region, countries outside of this region, in addition to the United States, all of whom are prepared to engage in military assistance, in actual strikes if that is what it requires," he said in an interview on CBS's "Face the Nation."

Some countries have said they are prepared to launch airstrikes in coordination with the US in the fight against Islamic State ( IS) militants, said Kerry, adding, however, that it's "not appropriate" to start announcing each country's plan.

"We're not looking to put troops on the ground. There are some who have offered to do so, but we are not looking for that, at this moment anyway," he said in Egyptian capital Cairo.

Kerry has been traveling throughout the Middle East working to build a coalition of nations to fight IS militants. The top US diplomat rejected the possibility of coordinating the military operation with the Syrian government.

"We're not going to coordinate it with Syria," Kerry said. "We will certainly want to de-conflict and make certain that they're not about to do something that they might regret even more seriously. But we're not going to coordinate, it's not a cooperative effort."

In the interview, Kerry backtracked on the language he had used to describe the fight against the Islamic State, saying that "we are at war" with the IS.

"I think there's frankly a kind of tortured debate going on about terminology," said Kerry, who rejected the word "war" in a previous interview with CBS.

"In terms of al-Qaida, which we have used the word 'war' with, yeah...we are at war with al-Qaida and its affiliates. And in the same context if you want to use it, yes, we are at war with ISIL in that sense," Kerry said, using an alternate acronym for the group.