Former U.K. Prime Minister Tony Blair said Monday it's going to be a "long, hard struggle" against the ideology of the Islamic State terrorist group that carried out the Nov. 13 Paris attacks and inspired last week's rampage in San Bernardino, California.

Blair told CNBC's "Squawk Box" he supports destroying ISIS by all means necessary — both by airstrikes and by aiding regional forces on the ground. "There is a lot that we can do to help the other people in the lead on the ground."

"Airstrikes only really work if you've got coordination between force on the ground and the airstrikes," he said. "You're not going take a group like ISIS out that have got an amount of territory roughly equivalent to the size of the U.K. ... simply by airstrikes."

Last week, the British parliament authorized and the U.K. military carried out airstrikes against ISIS in Syria.

The U.S. has been conducting an air campaign and using special forces against ISIS, and President Barack Obama on Sunday night set out his plan to fight the terrorist group.

Read More Obama: We will destroy ISIS, and here's how



Blair advocated a message of "religious tolerance, peaceful coexistence" while dealing "with the wider ideology of extremism that, I think, is part of the culture of hatred."

He also sees as key changing the way many Muslim children in parts of the world are taught a "closed-mined view of their religion and a closed-mined view of the world."



During his tenure, Blair was a key partner with President George W. Bush in the international military campaigns in Iraq and Afghanistan after the Sept. 11, 2001, terrorist attacks in the United States.