James Cooney said the agents would help with security, but Russia would be responsible for ensuring safety at the games, the Wall Street Journal reported Thursday.
The goal of the FBI's presence in the country, he said, is "to make sure the channel is open -- they need to know something that might be responsive to the threat, that we're there to be able to respond very quickly."
"I think it's particularly challenging in Sochi," Cooney added, "because of its proximity to areas of unrest and sources of a terrorist threat," the Washington Post reported.
Russian President Vladimir Putin has ordered increased security in the region where the games will be held after at least 34 people were killed in recent weeks by two bombs in Volgograd, a city about 425 miles from the Olympic site.
Cooney said the level of cooperation between the Russian and U.S. agencies was showing signs of improvement. Relations had fallen last year following the Boston Marathon bombings when Russia initially failed to reveal that one of the suspects in the bombings had been on their intelligence radar for some time.
The director said the FBI was also "deeply involved" in preparing the NFL Super Bowl, scheduled for Feb. 2 in New Jersey, the Los Angeles Times reported.