WASHINGTON, Sept. 7 -- U.S. President Barack Obama said he will make a speech on Wednesday to outline his plans for fighting the Islamic State militant group that does not involve a major ground offensive.

"I'm preparing the country to make sure that we deal with a threat from ISIL," the president said on NBC's "Meet the Press" program aired on Sunday, using another acronym for the radical group.

"This is not going to be an announcement about U.S. ground troops," he added.

The Obama administration said on Friday that it had built a " core coalition" to combat the Islamic State in Iraq, whose fighters had seized vast swaths of territory in northern Iraq since June and announced the establishment of a caliphate in areas under its control in both Syria and Iraq.

Obama came under immediate attacks after acknowledging late last mouth that he did not have a strategy yet for dealing with the rampaging militants.

Addressing a press conference on Friday as NATO wrapped up a summit in Wales, Obama vowed to "degrade and ultimately defeat" the group, which had beheaded two American journalists.

U.S. warplanes have bombed targets of the Islamic State in northern Iraq since Aug. 8, and Obama approved surveillance flights over war-torn Syria in late August.

U.S. military personnel have been sent into Iraq in batches since June to assess the threat posed by the Islamic State.

"The next phase is now to start going on some offense," Obama told NBC. "What this is is similar to the kinds of counterterrorism campaigns that we've been engaging in consistently over the last five, six, seven years."

"We are going to be as part of an international coalition, carrying out airstrikes in support of work on the ground by Iraqi troops, Kurdish troops," he said of his upcoming plans. "We are going to be helping to put together a plan for them, so that they can start retaking territory that ISIL had taken over."

"There's going to be an economic element to this," Obama said. "There's going to be a political element to it. There's going to be a military element to it."

He gave no more details, but made clear about his objective.

"What I want people to understand, though, is that over the course of months, we are going to be able to not just blunt the momentum of ISIL. We are going to systematically degrade their capabilities. We're going to shrink the territory that they control. And ultimately we're going to defeat 'em," the president said.

He said he believes he has the authority to act without congressional approval.

"I'm confident that I have the authorization that I need to protect the American people, and I'm always going to do what's necessary to protect the American people," he said.

"But I do think it's important for Congress to understand what the plan is, to have buy in, to debate it," he added.