Secretary of Defense James Mattis said the fight against the Islamic State of Iraq and Syria ((ISIS) has "accelerated" and shifted to "annihilation tactics."

"Our strategy right now is to accelerate the campaign against ISIS. It is a threat to all civilized nations," Mattis said in an interview that aired Sunday on CBS News' "Face the Nation."

Mattis made the comments shortly after President Trump returned from his first foreign trip, where he focused on combating ISIS and terrorism in general. On his first stop in Saudi Arabia, the president called on Muslim nations to unite against terrorists and "drive them out of this Earth."

Mattis used equally tough language. He said the "bottom line is we are going to move in an accelerated and reinforced manner, throw them on their back foot."

"We have already shifted from attrition tactics where we shove them from one position to another in Iraq and Syria, to annihilation tactics where we surround them," Mattis said. "Our intention is that the foreign fighters do not survive the fight to return home to North Africa, to Europe, to America, to Asia, to Africa. We're not going to allow them to do so. We're going to stop them there and take apart the caliphate."

The newer strategy gives ISIS no retreat, Mattis explained.

"You see that right now, for example, in western Mosul that is surrounded and the Iraqi -- security forces are moving against them," he said. "Tal Afar is now surrounded. We have got efforts underway right now to surround their self-declared caliphate capital of Raqqa. That surrounding operation is going on. And once surrounded, then we'll go in and clean them out."

One ISIS is annihilated, another challenge continues: making sure another group doesn't rise up to take its place.

"Once ISIS is defeated -- there's a larger effort underway to make certain that we don't just sprout a new enemy," Mattis said. "We know ISIS is going to go down. We've had success on the battlefield. We've freed millions of people from being under their control, and not one inch of that ground that ISIS has lost has ISIS regained."

"It shows the effectiveness of what we're doing," Mattis continued. "However, there are larger currents, there are larger confrontations in this part of the world, and we cannot be blind to those. That is why they met in Washington under Secretary (of State) Tillerson's effort to carry out President Trump's strategy to make certain we don't just clean out this enemy and end up with a new enemy in the same area."

Mattis declined to give a timeline for the fight against ISIS, only saying that it will be "long."

This is going to be a long fight," Mattis said. "The problems that we confront are going to lead to an era of frequent skirmishing. We will do it by, with, and through other nations. We will do it through developing their capabilities, to do a lot of the fighting, we'll help them with intelligence. Certainly, we can help train them for what they face. And you see our forces engaged in that from Africa to Asia. But at the same time, this is going to be a long fight and I don't put timelines on fights."