(CNN) -

A good soldier never publicly contradicts the commander in chief, at least not intentionally, and Defense Secretary Chuck Hagel is a good soldier.

A Vietnam War veteran, Hagel provided a robust defense of President Barack Obama's approach to ISIS jihadists in Iraq and Syria when interviewed Wednesday by CNN National Security Correspondent Jim Sciutto.

With Obama facing criticism over what even a fellow Democrat called too much caution, Hagel sought to make clear that the President wants to eliminate any ISIS threat to the United States and its interests -- both abroad and at home.

'Degrade and destroy'

"We're providing the President with those options to degrade and destroy" the ability of the group that calls itself the Islamic State to attack Americans anywhere in the world, he said.

When Sciutto pressed for clarity on Obama's statement earlier Wednesday , asking if the President meant containment, Hagel sough to clarify what his boss said.

Asked whether Obama meant "containment" when he said earlier Wednesday that the goal was to manage the ISIS threat, Hagel said, "No, it's not contain."

"It's exactly what the President said: Degrade and destroy."

And so it went for an hour of questions from Sciutto and some in the audience at the Naval War College in Newport, Rhode Island. Hagel repeatedly expressed agreement with Obama's positions on Syria and Ukraine, where the international community has said Russian troops have crossed the border to help pro-Russian separatists fighting the Ukrainian military.

Asked if Obama tipped his hand by rejecting a U.S. ground invasion against ISIS three years after bringing home combat forces from Iraq, Hagel said, "We're not going to go back into Iraq the same way we came out of Iraq a few years ago."

Instead, he advocated Obama's broad-based strategy that calls for a new and more inclusive Iraqi government, an international coalition supporting it and limited U.S. military action like the airstrikes launched last month at ISIS targets in the north.

"There's no question in my mind" that the Obama administration approached the ISIS issue with a "sense of urgency," Hagel said, adding that possible airstrikes on the jihadists' positions in Syria were among the options the Pentagon has presented to the President for further steps.

On the Ukraine conflict, Hagel sounded a similar theme. If Russian President Vladimir Putin continued to escalate the fighting there, he would face further consequences on top of U.S. and European Union sanctions imposed so far, but "we're not going to get into a military engagement, a war, over this with Russia," Hagel said.

'Sick to your stomach'

The ISIS issue dominated the hour-long interview. Hagel said the videotaped beheadings of two American journalists by the Sunni jihadists "makes you sick to your stomach, but it again reminds you of the brutality and barbarism that is afoot in some places in the world."

"It won't just recede into the gray recesses of history until we stop it," he said.

At one point, Hagel misspoke about the number of Americans believed fighting with ISIS.

"As we have acknowledged publicly, we are aware of over 100 U.S. citizens who have U.S. passports who are fighting in the Middle East with ISIL forces," he said, referring to the group by another acronym for the Sunni jihadists used by some U.S. officials. "There may be more -- we don't know."

The Pentagon later told Sciutto that Hagel's figure referred to the total number of Americans believed fighting in Syria with various groups, not just ISIS. About a dozen Americans are thought to be with ISIS.