OTTAWA — Thorsten Heins, the president and chief executive of BlackBerry, acknowledged on Tuesday that the company’s new line of phones, which he originally promoted as something that would revive its flagging brand, had a flawed release in the United States.

But Mr. Heins, speaking at the company’s annual meeting, told investors BlackBerry just needed more time for a turnaround — and he again sought their patience.

Not everyone was biting. One shareholder, referring to one of the new phones, the BlackBerry Z10, told Mr. Heins: “My sense is that the rollout of the Z10 was a disaster.”

“Were we perfect at the launch?” Mr. Heins responded. “Probably not. Was it a disaster? I don’t think so.”