(Bloomberg) -- President Joe Biden warned that Russia is weighing a cyberattack against the U.S. and urged private businesses to enhance their defenses.

Biden said in a statement that Russia “could conduct malicious cyber activity against the United States, including as a response to the unprecedented economic costs we’ve imposed” in response to the Ukraine invasion.

The administration has “evolving intelligence that the Russian government is exploring options for potential cyberattacks,” he added, and said the U.S. private sector should “harden your cyber defense immediately.”’

“Most of America’s critical infrastructure is owned and operated by the private sector and critical infrastructure owners and operators must accelerate efforts to lock their digital doors,” he said.

James Lewis, director of the strategic technologies program at the Center for Strategic and International Studies, said Russia was unlikely to “do something big” in order to avoid U.S. retaliation, but that frustration with its slow military progress against Kyiv might prompt the Kremlin to turn to a smaller cyberattack or ransomware attack.

“This is a wake-up call to people,” he said. “The Russians have explored U.S. critical infrastructure before in very extensive ways.”

(Updates with additional remarks beginning in second paragraph)

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