The chairman of Donald Trump's national security advisory committee offered a rare critique of his candidate Monday morning.

In an interview with CNN, Sen. Jeff Sessions, R-Ala., both defended and criticized Trump for claiming that President Obama and Hillary Clinton are the "founders of ISIS."

"Everybody knows that Clinton and Obama didn't meet to plot the foundation of ISIS," Sessions said. "So yeah, [Trump] stirred things up with that comment. You can say it was smart and not smart."

However, that comment had a "fundamental truth to it," Sessions quipped.

"Huge errors by our own administration allowed ISIS to come on the scene in a powerful way," Sessions added.

Sessions also gave a preview of Trump's Monday afternoon speech on national security and the Islamic State terror group.

"I think he is going to be direct and unvarnished. He is going to lay out the threat that we have from ISIS," Sessions said, adding he will talk about how to accomplish a "long-term idealogical battle" against the group.

He added: "[H]e is going to attack the Obama and Hillary Clinton policies that have created instability in Iraq, Syria, Libya and have created bases for ISIS and all those areas. So in a way, their policies, destabilizing their countries, did in fact create and nurture ISIS."