This post has been updated. 

Is the United States at war with the Islamic State? The answer depends on which official you ask.

President Obama on Wednesday announced an open-ended campaign to fight the Islamic State in Iraq and Syria. He called it a "comprehensive and sustained counterterrorism strategy." The word 'war' was never uttered by him.

But it was by White House Press Secretary Josh Earnest, who said Friday that the United States is, in fact, at war with the group.

"The United States is at war with ISIL in the same way that we are at war with al-Qaida and its al-Qaida affiliates all around the globe," Earnest said, using an acronym for the Islamic State.

"The fact is, ISIL has indicated that they’re ready to go to war against the world, and this president, as is expected of American presidents, is stepping up to lead an international coalition to confront that threat and to deny ISIL a safe haven. And ultimately this international coalition will be responsible for degrading and destroying ISIL," he said.

 The comments come after Secretary of State John Kerry said that war is the wrong term for the mission against the Islamic State, which beheaded two American journalists last month. 

"No,' Kerry told ABC News when asked if the U.S. is at war with the Islamic State. "Look, we’re engaged in a counterterrorism operation of a significant order," the secretary responded. "And counterterrorism operations can take a long time, they go on. I think 'war' is the wrong reference term with respect to that, but obviously it involves kinetic military action."

Speaking on CNN, National Security Adviser Susan Rice Thursday put the action in the realm of a counterterrorism campaign.

" I don't know whether you want to call it a war or sustained counterterrorism campaign. I think, frankly, this is a counterterrorism operation that will take time. It will be sustained," she said.

Pentagon spokesman Rear Admiral John Kirby said Friday that the action against the Islamic State is not like the Iraq war of 2002. As President Obama has said, action against the Islamic State will not involve American combat troops, but sustained air strikes and partnering with local troops.

"But make no mistake, we know we are at war with ISIL in the same way we are at war and continue to be at war with al-Qaeda and its affiliates," Kirby said.

A senior State Department official said the administration calibrated its language and Kerry would have changed his wording if he were asked about the Islamic State Friday rather than Thursday.

"This was a deliberate administration wide adjustment in language," said the official. "The language he used yesterday is consistent with what other senior officials have been saying," including Rice's interview.

A formal declaration of war requires an act of Congress. What officials seem to be conveying with the word 'war' is that, as President Obama said, the fight against the Islamic State will involve military might and will take time -- how much time, no one knows.

Anne Gearan contributed to this report.