Brennan disclosed Saturday that Obama opposed a plan to carry out “a cyber event” against the Russians because the former president feared the action would lead to more aggressive interference by Moscow.

“There was consideration about rattling their cages with some type of cyber event,” Brennan said during remarks to a journalism conference at the University of California Berkeley.

But based on Obama’s fears, the planned cyber action was shelved in favor issuing vague warnings to Russian officials. Brennan did not elaborate on the cyber retaliation plan.

“President Obama was the ultimate decision-maker on that,” Brennan said of the lack of response.