US President Barack Obama is to set out his "game plan" against Islamic State militants in a speech on Wednesday.
Mr Obama, who has been criticised for failing to outline a strategy, told NBC TV the US would degrade IS, shrink their territory and "defeat them".
US jets bombed IS targets in western Iraq for the first time on Sunday.
Meanwhile, the Arab League has vowed to take "all necessary measures" against IS, which has seized a huge amount of territory from Iraq and Syria.
The league gave its backing to a Security Council resolution passed last month calling on member states to stem the flow of weapons and money to extremists in Iraq and Syria.
BBC World Service Middle East editor Sebastian Usher says the Arab League's message will hearten Mr Obama, but the question now is whether its members will fully act on it, and act together rather than against each other.
'No ground troops'
Speaking on NBC's Meet the Press, Mr Obama said: "I'm preparing the country to make sure that we deal with a threat from Isil."
IS, also often referred to as Isil or Isis, has taken over large swathes of Iraq and Syria in recent months, declaring the land it controls a "caliphate".
Mr Obama went on: "On Wednesday, I'll make a speech and describe what our game plan's going to be going forward."