Former GOP presidential candidate Ben Carson on Tuesday suggested that multiple terrorist cells are operating on American soil.

“Look what’s going on in our country right now,” he told host Maria Bartiromo on Fox Business Network’s “Mornings with Maria." "We have a very, very weak border. Particularly with the southern border, but now we have to worry about the Canadian border as well.

“I’m sure we have multiple terrorist cells. We’re going to have to wake up very, very quickly here. We have to stop being politically correct and start protecting the American people.”

At least 30 people are dead and more than 100 others wounded following a series of coordinated terror attacks in Brussels earlier Tuesday morning.

Carson argued later that morning that extremists likely entered Belgium by taking advantage of Europe’s loose immigration regulations.

“It’s not unexpected,” he said of Tuesday’s massacre. "Obviously, we know there’s going to be continued attacks.

“One of the things that Europeans have done is really have a pretty lax policy when it comes to people coming from Syria and other places where they are likely to be terrorists. I’m sure that they are infiltrated.”

The Islamic State in Iraq and Syria (ISIS) is now claiming responsibility for Tuesday’s bloodshed, according to the Amaq news agency, an organization closely affiliated with the terrorist group.

Carson additionally charged on Tuesday that the U.S. must protect itself against radical Islamic terrorists and take immediate action against ISIS.

“We need to secure our borders,” the retired neurosurgeon said. "We need to stop just talking about it and start doing it.

“We need to go ahead and declare war on ISIS and reevaluate all of our immigration policies,” added Carson, who has endorsed GOP presidential front-runner Donald TrumpDonald John TrumpFamily immigration detention centers could be at capacity within days: report Trump likely to meet with Putin in July: report DOJ requests military lawyers to help prosecute immigration crimes: report MORE.

“[We need to] act when we see something and not be afraid that somebody’s going to call us ‘Islamophobic.' These are the things that are going to make a real difference."