DoubleLine Capital CEO Jeffrey Gundlach warned that the next US downturn could trigger a debt crisis, sending long-term Treasury yields sharply higher—defying the conventional wisdom that bonds serve as a safe haven during economic strife.

Such a scenario could push the Federal Reserve and the Treasury into unconventional policies, such as the central bank buying long-dated bonds in a repeat of Operation Twist, or even a debt restructuring.

Gundlach said he’s focusing on low-duration assets to shield DoubleLine’s funds against further increases in interest rates.