He said there was no evidence the Russian planes posed a direct threat. Tu-142 Bears are primarily reconnaissance and anti-submarine aircraft.
Still, the carrier scrambled four F/A-18 fighters to intercept and escort the Russian aircraft, he said.
One of the US ships accompanying the USS Ronald Reagan tried to hail the Russian aircraft by radio but did not receive a response, he added.
"It's standard operating procedure for US planes to escort any aircraft that are flying anywhere in the vicinity of US Navy ships," Davis said. "The interaction was characterized as safe."
"Any time there are aircraft that are operating in close proximity to a US Navy ship, particularly an aircraft carrier, we are going to take action to launch and make sure we are tracking it very closely," Davis said.
He said this kind of incident is not unprecedented, noting: "It doesn't happen frequently but this did occur."
The incident comes after Russia and the United States on October 10 signed a memorandum of understanding that establishes protocols for pilots flying over Syria.
Both Russia and a US-led coalition are conducting separate bombing campaigns in the war-torn country. Though they are mainly operating in different regions, officials are worried about planes crashing into each other in the sky.