Tens of thousands of military and police personnel have been deployed to protect the games, as well as warships, anti-missile batteries and drone aircraft. Two U.S. warships have been dispatched to the Black Sea ahead of the games.
"Every big event nowadays is under threat, whether it's a political summit or a big convention," Bach said. "We have to address this because anything else would be surrender to terrorists and this is the last thing we all want to do."
Bach said the security operation was comparable to that for the 2002 Salt Lake City Games, held just a few months after the Sept. 11, 2001, terror attacks in the U.S.
"There was very heavy security, yet in all the venues you could enjoy very good Olympic atmosphere and I think the same will happen here," he said. "I think the atmosphere can really flourish."
Bach also restated his position that the Russian law banning gay "propaganda" among minors would not impact the games.
"The IOC has made it very clear: We stand against any form of discrimination," he said.
Bach has received assurances from Russian President Vladimir Putin that athletes and visitors will not face any discrimination on the basis of sexual orientation.
The IOC Charter says discrimination "on grounds of race, religion, politics, gender or other otherwise is incompatible with belonging to the Olympic movement."
Asked whether the rule could be amended to include sexual orientation, Bach insisted it was already covered by the language in the charter.
"Sexual orientation is included in the charter — whether you name it expressly or not is more symbolic an issue," he said. "It doesn't change the legal quality."
Bach defended the cost of the games, whose total price tag — including spending on roads, railway lines, hotels and other infrastructure projects — is $51 billion, a record for any Winter or Summer Olympics.
Bach said Sochi's actual operating costs were in line with previous games, or several billion dollars. The extra tens of billions of dollars, he said, were part of Russia's long-term investment to turn the area from a faded summer resort into a year-round destination and winter sports complex for the whole country.
"The games are serving as the catalyst," he said.
Bach also said he was confident organizers would sort out the problems of hotel accommodations that are not ready for some Olympic-accredited personnel, especially in the mountain areas.