Federal regulators along with Congress are planning an unprecedented and sweeping review of the world's largest tech companies in an effort to determine whether the companies are harming competition and consumers. A source within the tech industry tells CBS News that Google, Apple, Facebook and Amazon are the targets of potential antitrust probes. Shares of Apple, Facebook, Amazon and Google's parent company Alphabet all dropped following word of the investigations.

Norah O'Donnell, the incoming anchor and managing editor of the "CBS Evening News," sat down with Apple CEO Tim Cook in San Jose, California for an exclusive interview after his keynote address at Monday's annual Worldwide Developers Conference where the company announced a range of new software features for its devices and the retirement of iTunes. O'Donnell asked Cook about those changes and ramped-up government scrutiny.

NORAH O'DONNELL: The government is looking into big tech. Essentially, whether companies like Facebook, Google, and Apple are too big. Is Apple too big?

TIM COOK: No. I don't think so. I think that with – but with size, I think scrutiny is fair. I think we should be scrutinized. But if you look at our – any kind of measure about is Apple a monopoly or not, I don't think anybody reasonable is gonna come to the conclusion that Apple's a monopoly. Our share is much more modest. We don't have a dominant position in any market … You know, our share of smart phones in the U.S. is typically in the high 30s or so, mid-30s. On PCs, it's lower than that. And so on and so forth and so --

O'DONNELL: You're saying you're not a monopoly.

COOK: We are not a monopoly.

O'DONNELL: But Elizabeth Warren, who is campaigning for president says, "Apple should break up its app Store and other parts of its business."



TIM COOK: Well, I strongly disagree with that. I think some people would argue, if you are selling a good, then you can't have a product that competes with that good. And I think that's part of what is being argued there. But that's an argument, Norah, that takes you down the path that, Walmart shouldn't be stocking alternative or house brand … And so this is decades of U.S. law here. But I think scrutiny is good, and we'll be – we'll tell our story to anybody that we need to or that wants to hear it.

Tune in to the "CBS Evening News" on Tuesday, June 4 for much more of O'Donnell's exclusive interview with Cook. They'll discuss his relationship with President Trump and why even Cook says we are using our phones too much.