Apple is preparing to raise prices, and CEO Tim Cook is pointing to one main culprit: the soaring cost of the memory and storage chips inside its devices.

In an exclusive interview with Rolfe Winkler of The Wall Street Journal, Cook said price increases are "unavoidable" as the company works to offset surging chip costs. He went further, telling the Journal that "the situation has become unsustainable."

The pressure centers on memory. According to The Verge, which covered the same Wall Street Journal interview, Apple is planning to raise prices in response to an ongoing memory shortage, with Cook describing RAM expenses as "unsustainable."

Cook framed the move as a last resort rather than a quick grab for higher margins. "We're doing our best to mitigate the huge increases that are being passed to us, and we've been trying to shield our" customers, he told The Wall Street Journal, in remarks quoted by The Verge.

Neither source detailed exactly which products would cost more, by how much, or when the new prices would take effect. What the reporting establishes is the cause Apple is naming publicly: the rising price of memory and storage components that go into nearly every device it sells.

Why it matters: when one of the world's largest and most cost-disciplined hardware makers says it can no longer absorb chip costs and must pass them to customers, it signals that the memory squeeze is real enough to reach consumers' wallets—and that buyers of phones, laptops and tablets may soon pay more.