Following up on yesterday's report that the Pentagon is likely to recommend a significant deployment of US ground troops to Syria by month's end, Defense Secretary James Mattis confirmed that the US, as well as NATO as an alliance, are preparing to escalate the fight against ISIS in both Iraq and Syria.

Mattis played up the idea of a "sustained effort" to fight against ISIS, saying it was a fight that needs to be accelerated, and one he is confident all of NATO is committed to accelerating, though he said the fight would not be over quickly.

At the same time, Mattis said he was not ready to embrace a specific recommendation for a deployment of ground troops, and wanted to talk with other NATO members before deciding on specifics. He did say he wouldn't rule out making such a recommendation, however.